### Summary

I have a task to conditionally install an SSH key on another machine:

```yaml
- authorized_key: ...
  delegate_to: "{{ jenkins_install_key_on }}"
  when: jenkins_install_key_on != ""
```

This works fine when `jenkins_install_key_on` is set to a non-blank value, but fails when `jenkins_install_key_on` is set to an empty string:

```
fatal: [jammy -> {{ jenkins_install_key_on }}]: FAILED! => {"msg": "Supplied entity must be Host or Group, got <class 'ansible.inventory.host.Host'> instead"}
```

It used to work with ansible-core 2.15 and older.

### Issue Type

Bug Report

### Component Name

delegate_to

### Ansible Version

```console
$ ansible --version
ansible [core 2.16.0]
  config file = /home/mg/src/deployments/provisioning/ansible.cfg
  configured module search path = ['/home/mg/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/mg/.local/pipx/venvs/ansible/lib/python3.11/site-packages/ansible
  ansible collection location = /home/mg/.ansible/collections:/usr/share/ansible/collections
  executable location = /home/mg/.local/bin/ansible
  python version = 3.11.6 (main, Oct  8 2023, 05:06:43) [GCC 13.2.0] (/home/mg/.local/pipx/venvs/ansible/bin/python)
  jinja version = 3.1.2
  libyaml = True
```


### Configuration

```console
# if using a version older than ansible-core 2.12 you should omit the '-t all'
$ ansible-config dump --only-changed -t all
ACTION_WARNINGS(/home/mg/src/deployments/provisioning/ansible.cfg) = False
CACHE_PLUGIN(/home/mg/src/deployments/provisioning/ansible.cfg) = jsonfile
CACHE_PLUGIN_CONNECTION(/home/mg/src/deployments/provisioning/ansible.cfg) = .cache/facts/
CACHE_PLUGIN_TIMEOUT(/home/mg/src/deployments/provisioning/ansible.cfg) = 86400
CALLBACKS_ENABLED(/home/mg/src/deployments/provisioning/ansible.cfg) = ['fancy_html']
CONFIG_FILE() = /home/mg/src/deployments/provisioning/ansible.cfg
DEFAULT_FORKS(/home/mg/src/deployments/provisioning/ansible.cfg) = 15
DEFAULT_GATHERING(/home/mg/src/deployments/provisioning/ansible.cfg) = smart
DEFAULT_HOST_LIST(/home/mg/src/deployments/provisioning/ansible.cfg) = ['/home/mg/src/deployments/provisioning/inventory']
DEFAULT_LOG_PATH(/home/mg/src/deployments/provisioning/ansible.cfg) = /home/mg/src/deployments/provisioning/.cache/ansible.log
DEFAULT_REMOTE_USER(/home/mg/src/deployments/provisioning/ansible.cfg) = root
DEFAULT_STDOUT_CALLBACK(/home/mg/src/deployments/provisioning/ansible.cfg) = yaml
DEFAULT_VAULT_PASSWORD_FILE(/home/mg/src/deployments/provisioning/ansible.cfg) = /home/mg/src/deployments/provisioning/askpas>
EDITOR(env: EDITOR) = vim
INTERPRETER_PYTHON(/home/mg/src/deployments/provisioning/ansible.cfg) = python3
RETRY_FILES_ENABLED(/home/mg/src/deployments/provisioning/ansible.cfg) = False

CACHE:
=====

jsonfile:
________
_timeout(/home/mg/src/deployments/provisioning/ansible.cfg) = 86400
_uri(/home/mg/src/deployments/provisioning/ansible.cfg) = /home/mg/src/deployments/provisioning/.cache/facts

CONNECTION:
==========

paramiko_ssh:
____________
remote_user(/home/mg/src/deployments/provisioning/ansible.cfg) = root

ssh:
___
remote_user(/home/mg/src/deployments/provisioning/ansible.cfg) = root
```


### OS / Environment

Ubuntu 23.10

### Steps to Reproduce

<!--- Paste example playbooks or commands between quotes below -->
```yaml (paste below)
- hosts: all
  gather_facts: no
  tasks:
    - debug: msg="hello"
      delegate_to: "{{ var }}"
      when: var != ""
      vars:
        var: ""
```


### Expected Results

I expect the task to be skipped.

### Actual Results

```console
$ ansible-playbook -i localhost, ansible-delegate-to-blank.yml -vvvv
ansible-playbook [core 2.16.0]
  config file = None
  configured module search path = ['/home/mg/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/mg/.local/pipx/venvs/ansible/lib/python3.11/site-packages/ansible
  ansible collection location = /home/mg/.ansible/collections:/usr/share/ansible/collections
  executable location = /home/mg/.local/bin/ansible-playbook
  python version = 3.11.6 (main, Oct  8 2023, 05:06:43) [GCC 13.2.0] (/home/mg/.local/pipx/venvs/ansible/bin/python)
  jinja version = 3.1.2
  libyaml = True
No config file found; using defaults
setting up inventory plugins
Loading collection ansible.builtin from 
Set default localhost to localhost
Parsed localhost, inventory source with host_list plugin
Loading callback plugin default of type stdout, v2.0 from /home/mg/.local/pipx/venvs/ansible/lib/python3.11/site-packages/ansible/plugins/callback/default.py
Skipping callback 'default', as we already have a stdout callback.
Skipping callback 'minimal', as we already have a stdout callback.
Skipping callback 'oneline', as we already have a stdout callback.

PLAYBOOK: ansible-delegate-to-blank.yml **************************************************************************************
Positional arguments: ansible-delegate-to-blank.yml
verbosity: 4
connection: ssh
become_method: sudo
tags: ('all',)
inventory: ('localhost,',)
forks: 5
1 plays in ansible-delegate-to-blank.yml

PLAY [all] *******************************************************************************************************************

TASK [debug] *****************************************************************************************************************
task path: /home/mg/tmp/ansible-delegate-to-blank.yml:4
fatal: [localhost -> {{ var }}]: FAILED! => {
    "msg": "Supplied entity must be Host or Group, got <class 'ansible.inventory.host.Host'> instead"
}

PLAY RECAP *******************************************************************************************************************
localhost                  : ok=0    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
'''
        Runs the task with the loop items specified and collates the result
        into an array named 'results' which is inserted into the final result
        along with the item for which the loop ran.
        '''
        task_vars = self._job_vars
        templar = Templar(loader=self._loader, variables=task_vars)
        self._task.loop_control.post_validate(templar=templar)
        loop_var = self._task.loop_control.loop_var
        index_var = self._task.loop_control.index_var
        loop_pause = self._task.loop_control.pause
        extended = self._task.loop_control.extended
        extended_allitems = self._task.loop_control.extended_allitems
        
        label = self._task.loop_control.label or '{{' + loop_var + '}}'
        if loop_var in task_vars:
            display.warning(u"%s: The loop variable '%s' is already in use. "
                            u"You should set the `loop_var` value in the `loop_control` option for the task"
                            u" to something else to avoid variable collisions and unexpected behavior." % (self._task, loop_var))
        ran_once = False
        task_fields = None
        no_log = False
        items_len = len(items)