##### SUMMARY
The PR https://github.com/ansible/ansible/pull/64156 deprecated passing extra variables on `import_playbook`, which was wrongly stated to have never worked before, but it does, as shown in the example below.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
- `import_playbook`

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.10.3
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/goetz/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3.8/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 3.8.6 (default, Sep 30 2020, 04:00:38) [GCC 10.2.0]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below
[no output]
```

##### OS / ENVIRONMENT
- GNU/Linux

##### STEPS TO REPRODUCE
`playbooks/site.yaml`:
```yaml
---
- hosts: "{{ target }}"
  roles:
    - role: my-role
```

`playbooks/dev.yaml`:
```yaml
---
- import_playbook: site.yml target='dev'
```

```sh
ansible-playbook playbooks/dev.yml
```

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
Playbook runs without warnings or errors.

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
Playbooks shows a Warning about this behavior going to fail in a future Ansible minor version update.
```sh
[WARNING]: Additional parameters in import_playbook statements are not supported. This will be an error in version 2.14
```


if not isinstance(version, (str, float)):
            self.add_message('invalid-version', node=node, args=(version,))
            return
        version_no = str(version)
        if collection_name == 'ansible.builtin':
            
            try:
                if not version_no:
                    raise ValueError('Version string should not be empty')
                loose_version = LooseVersion(str(version_no))
                if ANSIBLE_VERSION >= loose_version:
                    self.add_message('ansible-deprecated-version', node=node, args=(version,))
            except ValueError:
                self.add_message('ansible-invalid-deprecated-version', node=node, args=(version,))
        elif collection_name:
            
            try:
                if not version_no:
                    raise ValueError('Version string should not be empty')
                semantic_version = SemanticVersion(version_no)
                if collection_name == self.collection_name and self.collection_version is not None:
                    if self.collection_version >= semantic_version:
                        self.add_message('collection-deprecated-version', node=node, args=(version,))
                if semantic_version.major != 0 and (semantic_version.minor != 0 or semantic_version.patch != 0):
                    self.add_message('removal-version-must-be-major', node=node, args=(version,))
            except ValueError:
                self.add_message('collection-invalid-deprecated-version', node=node, args=(version,))
    @check_messages(*(MSGS.keys()))
    def visit_call(self, node):