### 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
'Prepend the value with + to fail if no valid signatures are found for the collection (e.g. +all).'
        ignore_gpg_status_help = 'A status code to ignore during signature verification (for example, NO_PUBKEY). ' \
                                 'Provide this option multiple times to ignore a list of status codes. ' \
                                 'Descriptions for the choices can be seen at L(https://github.com/gpg/gnupg/blob/master/doc/DETAILS#general-status-codes).'
        verify_parser.add_argument('--required-valid-signature-count', dest='required_valid_signature_count', type=validate_signature_count,
                                   help=valid_signature_count_help, default=C.GALAXY_REQUIRED_VALID_SIGNATURE_COUNT)
        verify_parser.add_argument('--ignore-signature-status-code', dest='ignore_gpg_errors', type=str, action='append',
                                   help=ignore_gpg_status_help, default=C.GALAXY_IGNORE_INVALID_SIGNATURE_STATUS_CODES,
                                   choices=list(GPG_ERROR_MAP.keys()))
    def add_install_options(self, parser, parents=None):
        galaxy_type = 'collection' if parser.metavar == 'COLLECTION_ACTION' else 'role'
        args_kwargs = {}
        if galaxy_type == 'collection':
            args_kwargs['help'] = 'The collection(s) name or path/url to a tar.gz collection artifact. This is ' \
                                  'mutually exclusive with --requirements-file.'
            ignore_errors_help = 'Ignore errors during installation and continue with the next specified ' \
                                 'collection. This will not ignore dependency conflict errors.'
        else:
            args_kwargs['help'] = 'Role name, URL or tar file'
            ignore_errors_help = 'Ignore errors and continue with the next specified role.'
        install_parser = parser.add_parser('install', parents=parents,
                                           help='Install {0}(s) from file(s), URL(s) or Ansible '
                                                'Galaxy'.format(galaxy_type))
        install_parser.set_defaults(func=self.execute_install)
        install_parser.add_argument('args', metavar='{0}_name'.format(galaxy_type), nargs='*', **args_kwargs)
        install_parser.add_argument('-i', '--ignore-errors', dest='ignore_errors', action='store_true', default=False,
                                    help=ignore_errors_help)
        install_exclusive = install_parser.add_mutually_exclusive_group()
        install_exclusive.add_argument('-n', '--no-deps', dest='no_deps', action='store_true', default=False,
                                       help="Don't download {0}s listed as dependencies.".format(galaxy_type))