### 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 isinstance(v, list):
                v = ". ".join([l.rstrip('.') for l in v])
            v = link_pattern.sub(r"\1 <\2>", v)
            v = const_pattern.sub(r"'\1'", v)
            return textwrap.fill(v, width=117, initial_indent="# ", subsequent_indent="# ", break_on_hyphens=False)
        loader = DataLoader()
        templar = Templar(loader, variables={'required_config': required_config, 'optional_config': optional_config})
        templar.environment.filters['comment_ify'] = comment_ify
        meta_value = templar.template(meta_template)
        return meta_value
    def _require_one_of_collections_requirements(
            self, collections, requirements_file,
            signatures=None,
            artifacts_manager=None,
    ):
        if collections and requirements_file:
            raise AnsibleError("The positional collection_name arg and --requirements-file are mutually exclusive.")
        elif not collections and not requirements_file:
            raise AnsibleError("You must specify a collection name or a requirements file.")
        elif requirements_file:
            if signatures is not None:
                raise AnsibleError(