### 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 'artifacts_manager' in kwargs:
            return wrapped_method(*args, **kwargs)
        artifacts_manager_kwargs = {'validate_certs': context.CLIARGS['validate_certs']}
        keyring = context.CLIARGS.get('keyring', None)
        if keyring is not None:
            artifacts_manager_kwargs.update({
                'keyring': GalaxyCLI._resolve_path(keyring),
                'required_signature_count': context.CLIARGS.get('required_valid_signature_count', None),
                'ignore_signature_errors': context.CLIARGS.get('ignore_gpg_errors', None),
            })
        with ConcreteArtifactsManager.under_tmpdir(
                C.DEFAULT_LOCAL_TMP,
                **artifacts_manager_kwargs
        ) as concrete_artifact_cm:
            kwargs['artifacts_manager'] = concrete_artifact_cm
            return wrapped_method(*args, **kwargs)
    return method_wrapper
def _display_header(path, h1, h2, w1=10, w2=7):
    display.display('\n# {0}\n{1:{cwidth}} {2:{vwidth}}\n{3} {4}\n'.format(
        path,
        h1,
        h2,
        '-' * max([len(h1), w1]),  
        '-' * max([len(h2), w2]),
        cwidth=w1,
        vwidth=w2,
    ))
def _display_role(gr):