##### 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
```


from __future__ import (absolute_import, division, print_function)
__metaclass__ = type
import datetime
import re
from distutils.version import LooseVersion
import astroid
from pylint.interfaces import IAstroidChecker
from pylint.checkers import BaseChecker
from pylint.checkers.utils import check_messages
from ansible.module_utils.six import string_types
from ansible.release import __version__ as ansible_version_raw
from ansible.utils.version import SemanticVersion
MSGS = {
    'E9501': ("Deprecated version (%r) found in call to Display.deprecated "
              "or AnsibleModule.deprecate",
              "ansible-deprecated-version",
              "Used when a call to Display.deprecated specifies a version "
              "less than or equal to the current version of Ansible",
              {'minversion': (2, 6)}),
    'E9502': ("Display.deprecated call without a version or date",
              "ansible-deprecated-no-version",
              "Used when a call to Display.deprecated does not specify a "
              "version or date",
              {'minversion': (2, 6)}),