### Summary

To reproduce, run these commands where `ns.col` is the name of a collection you do not have installed and the value of `-p` is a valid collection path that exists:

`ansible-galaxy collection list ns.col -p collections/`
`$?`

The output of $? on devel is 0, but since the collection wasn't found it should be 1. The same issue exists for listing specific roles that do not exist.

To fix:
1. [This method](https://github.com/ansible/ansible/blob/stable-2.14/lib/ansible/cli/galaxy.py#L1494-L1502) needs to return the correct exit code from `execute_list_role` and `execute_list_collection`.

2. `execute_list_collection` and `execute_list_role` will need to be fixed to return 1 if a collection/role was requested and not found.
For example, on [this line ](https://github.com/ansible/ansible/blob/stable-2.14/lib/ansible/cli/galaxy.py#L1680) add
```python
        if not collection_found and collection_name:
            return 1
```

3. Add a new test to [this file](https://github.com/ansible/ansible/blob/stable-2.14/test/integration/targets/ansible-galaxy-collection/tasks/list.yml), similar to [this one](https://github.com/ansible/ansible/blob/stable-2.14/test/integration/targets/ansible-galaxy-collection/tasks/list.yml#L111-L116) that lists a single collection that does not exist. Then add an assert task following it to test that the command result's rc is 1.

4. Add a `bugfixes` [changelog fragment](https://docs.ansible.com/ansible/latest/community/development_process.html#creating-a-changelog-fragment).

### Issue Type

Bug Report

### Component Name

ansible-galaxy

### Ansible Version

```console
$ ansible --version
ansible [core 2.15.0.dev0]
```


### 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
```


### OS / Environment

N/A

### Steps to Reproduce

<!--- Paste example playbooks or commands between quotes below -->
```bash (paste below)
ansible-galaxy collection list ns.col -p collections/
$?
```

### Expected Results

1

### Actual Results

```console
0
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
if v3:
                
                
                
                
                server_options['available_api_versions'] = {'v3': '/v3'}
            
            server_options['token'] = None
            if username:
                server_options['token'] = BasicAuthToken(username, server_options['password'])
            else:
                if token_val:
                    if auth_url:
                        server_options['token'] = KeycloakToken(access_token=token_val,
                                                                auth_url=auth_url,
                                                                validate_certs=validate_certs,
                                                                client_id=client_id)
                    else:
                        
                        server_options['token'] = GalaxyToken(token=token_val)
            server_options.update(galaxy_options)
            config_servers.append(GalaxyAPI(
                self.galaxy, server_key,
                priority=server_priority,
                **server_options
            ))
        cmd_server = context.CLIARGS['api_server']
        cmd_token = GalaxyToken(token=context.CLIARGS['api_key'])
        
        v_config_default = True if C.GALAXY_IGNORE_CERTS is None else not C.GALAXY_IGNORE_CERTS