### Summary

See: https://github.com/ansible/ansible/blob/devel/lib/ansible/modules/git.py#L760 :

```py
            repo_path = os.path.join(repo_path.split('.git')[0], gitdir)
```

the intention of this code seems to be to strip `.git` from the end of the path.

If the repo path contains `.git` anywhere, like `/tmp/music.gittern/myrepo`, tasks will unexpectedly fail:

```
fatal: [localhost]: FAILED! => {"changed": false, "details": "/tmp/music/../.git/modules/submodule is not a directory", "msg": "Current repo does not have a valid reference to a separate Git dir or it refers to the invalid path"}
```

For a playbook like:
```yaml
---
- hosts: localhost
  tasks:
   - name: test git
     git: 
        repo: ...
        dest: /tmp/music.gittern/myrepo/submodule
```

I can't tell if this is a potential security issue or just an unexpected corner case. What I am pretty sure I can tell, is that that's not how one strips `.git` from the end of a path.

### Issue Type

Bug Report

### Component Name

git

### Ansible Version

```console
$ ansible --version
2.11
```


### Configuration

```console
$ ansible-config dump --only-changed
ANSIBLE_NOCOWS(/home/enrico/dev/transilience/ansible.cfg) = True
```


### OS / Environment

Debian Bullseye

### Steps to Reproduce

Use submodules in a repo whose path contains `.git` anywhere as part of a file name.
For example:
```yaml
---
- hosts: localhost
  tasks:
   - name: test git
     git: 
        repo: ...
        dest: /tmp/music.gittern/myrepo/submodule
```

### Expected Results

I'd expect directory names like `gato.gito` not to be interpreted specially by mistake

### Actual Results

```console
fatal: [localhost]: FAILED! => {"changed": false, "details": "/tmp/music/../.git/modules/submodule is not a directory", "msg": "Current repo does not have a valid reference to a separate Git dir or it refers to the invalid path"}
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
update = module.params['update']
    allow_clone = module.params['clone']
    bare = module.params['bare']
    verify_commit = module.params['verify_commit']
    gpg_whitelist = module.params['gpg_whitelist']
    reference = module.params['reference']
    single_branch = module.params['single_branch']
    git_path = module.params['executable'] or module.get_bin_path('git', True)
    key_file = module.params['key_file']
    ssh_opts = module.params['ssh_opts']
    umask = module.params['umask']
    archive = module.params['archive']
    archive_prefix = module.params['archive_prefix']
    separate_git_dir = module.params['separate_git_dir']
    result = dict(changed=False, warnings=list())
    if module.params['accept_hostkey']:
        if ssh_opts is not None:
            if ("-o StrictHostKeyChecking=no" not in ssh_opts) and ("-o StrictHostKeyChecking=accept-new" not in ssh_opts):
                ssh_opts += " -o StrictHostKeyChecking=no"
        else:
            ssh_opts = "-o StrictHostKeyChecking=no"
    if module.params['accept_newhostkey']:
        if not ssh_supports_acceptnewhostkey(module):
            module.warn("Your ssh client does not support accept_newhostkey option, therefore it cannot be used.")
        else:
            if ssh_opts is not None:
                if ("-o StrictHostKeyChecking=no" not in ssh_opts) and ("-o StrictHostKeyChecking=accept-new" not in ssh_opts):
                    ssh_opts += " -o StrictHostKeyChecking=accept-new"
            else:
                ssh_opts = "-o StrictHostKeyChecking=accept-new"