### 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
display.vvv("No 'ansible_collections' directory found at {0}".format(collection_path))
                    continue
                if not collections:
                    display.vvv("No collections found at {0}".format(collection_path))
                    continue
                if output_format in {'yaml', 'json'}:
                    collections_in_paths[collection_path] = {
                        collection.fqcn: {'version': collection.ver} for collection in collections
                    }
                    continue
                
                fqcn_width, version_width = _get_collection_widths(collections)
                _display_header(collection_path, 'Collection', 'Version', fqcn_width, version_width)
                
                for collection in sorted(collections, key=to_text):
                    _display_collection(collection, fqcn_width, version_width)
        
        if collection_found and collection_name:
            warnings = []
        for w in warnings:
            display.warning(w)
        if not path_found:
            raise AnsibleOptionsError("- None of the provided paths were usable. Please specify a valid path with --{0}s-path".format(context.CLIARGS['type']))
        if output_format == 'json':
            display.display(json.dumps(collections_in_paths))
        elif output_format == 'yaml':
            display.display(yaml_dump(collections_in_paths))
        return 0
    def execute_publish(self):