### Summary

If the argument spec defines a dict variable as required:

- if the variable has no default in defaults/main.yml and is not provided in the playbook, argument spec validation will fail. That's OK.
- if the variable is defined as a string e.g. `''` or `'test-string'`, validation will fail. That's OK.
- if the variable is defines as None or `~`, validation will pass. That's NOT OK.

### Issue Type

Bug Report

### Component Name

argument_spec

### Ansible Version

```console
$ ansible --version
ansible [core 2.15.0.dev0] (devel 51bddd862b) last updated 2023/01/03 22:32:16 (GMT +000)
  config file = /home/nikos/projects/ansible-demo/ansible.cfg
  configured module search path = ['/home/nikos/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/nikos/projects/ansible/lib/ansible
  ansible collection location = /home/nikos/.ansible/collections:/usr/share/ansible/collections
  executable location = /home/nikos/projects/ansible/bin/ansible
  python version = 3.10.8 (main, Nov  1 2022, 14:18:21) [GCC 12.2.0] (/usr/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
ANSIBLE_NOCOWS(/home/nikos/projects/ansible-demo/ansible.cfg) = True
CACHE_PLUGIN(/home/nikos/projects/ansible-demo/ansible.cfg) = ansible.builtin.json
CACHE_PLUGIN_CONNECTION(/home/nikos/projects/ansible-demo/ansible.cfg) = facts_cache
CONFIG_FILE() = /home/nikos/projects/ansible-demo/ansible.cfg
DEFAULT_EXECUTABLE(/home/nikos/projects/ansible-demo/ansible.cfg) = /bin/bash
DEFAULT_GATHERING(/home/nikos/projects/ansible-demo/ansible.cfg) = implicit
DEFAULT_HOST_LIST(/home/nikos/projects/ansible-demo/ansible.cfg) = ['/home/nikos/projects/ansible-demo/inventory.ini']
DEFAULT_MANAGED_STR(/home/nikos/projects/ansible-demo/ansible.cfg) = \nAnsible managed (do not edit, changes may be overwritten)
EDITOR(env: EDITOR) = nvim

CACHE:
=====

jsonfile:
________
```


### OS / Environment

Controller and target: Arch Linux

### Steps to Reproduce

<!--- Paste example playbooks or commands between quotes below -->
```yaml (paste below)
# role argument specs
---

argument_specs:
  main:
    options:
      dict_var:
        type: dict
        required: true
```

```
# playbook
---

- hosts: all
  roles:
    - myrole
  vars:
    dict_var: ~
```

### Expected Results

I expect argument validation to fail with a message that None type is not dict or could not be converted to dict.

### Actual Results

```console
Validation passes and role execution succeeds.
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
"""Validate that parameter types match the type in the argument spec.
    Determine the appropriate type checker function and run each
    parameter value through that function. All error messages from type checker
    functions are returned. If any parameter fails to validate, it will not
    be in the returned parameters.
    :arg argument_spec: Argument spec
    :type argument_spec: dict
    :arg parameters: Parameters
    :type parameters: dict
    :kwarg prefix: Name of the parent key that contains the spec. Used in the error message
    :type prefix: str
    :kwarg options_context: List of contexts?
    :type options_context: list
    :returns: Two item tuple containing validated and coerced parameters
              and a list of any errors that were encountered.
    :rtype: tuple
    """
    if errors is None:
        errors = AnsibleValidationErrorMultiple()
    for param, spec in argument_spec.items():
        if param not in parameters:
            continue
        value = parameters[param]
        if value is None: