### 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
info_parser = parser.add_parser('info', parents=parents, help='View more details about a specific role.')
        info_parser.set_defaults(func=self.execute_info)
        info_parser.add_argument('args', nargs='+', help='role', metavar='role_name[,version]')
    def add_verify_options(self, parser, parents=None):
        galaxy_type = 'collection'
        verify_parser = parser.add_parser('verify', parents=parents, help='Compare checksums with the collection(s) '
                                          'found on the server and the installed copy. This does not verify dependencies.')
        verify_parser.set_defaults(func=self.execute_verify)
        verify_parser.add_argument('args', metavar='{0}_name'.format(galaxy_type), nargs='*', help='The installed collection(s) name. '
                                   'This is mutually exclusive with --requirements-file.')
        verify_parser.add_argument('-i', '--ignore-errors', dest='ignore_errors', action='store_true', default=False,
                                   help='Ignore errors during verification and continue with the next specified collection.')
        verify_parser.add_argument('--offline', dest='offline', action='store_true', default=False,
                                   help='Validate collection integrity locally without contacting server for '
                                        'canonical manifest hash.')
        verify_parser.add_argument('-r', '--requirements-file', dest='requirements',
                                   help='A file containing a list of collections to be verified.')
        verify_parser.add_argument('--keyring', dest='keyring', default=C.GALAXY_GPG_KEYRING,
                                   help='The keyring used during signature verification')  
        verify_parser.add_argument('--signature', dest='signatures', action='append',
                                   help='An additional signature source to verify the authenticity of the MANIFEST.json before using '
                                        'it to verify the rest of the contents of a collection from a Galaxy server. Use in '
                                        'conjunction with a positional collection name (mutually exclusive with --requirements-file).')
        valid_signature_count_help = 'The number of signatures that must successfully verify the collection. This should be a positive integer ' \
                                     'or all to signify that all signatures must be used to verify the collection. ' \