### 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 install_info:
                if 'version' in install_info:
                    install_info['installed_version'] = install_info['version']
                    del install_info['version']
                role_info.update(install_info)
            if not context.CLIARGS['offline']:
                remote_data = None
                try:
                    remote_data = self.api.lookup_role_by_name(role, False)
                except AnsibleError as e:
                    if e.http_code == 400 and 'Bad Request' in e.message:
                        
                        data = u"- the role %s was not found" % role
                        break
                    raise AnsibleError("Unable to find info about '%s': %s" % (role, e))
                if remote_data:
                    role_info.update(remote_data)
            elif context.CLIARGS['offline'] and not gr._exists:
                data = u"- the role %s was not found" % role
                break
            if gr.metadata:
                role_info.update(gr.metadata)
            req = RoleRequirement()
            role_spec = req.role_yaml_parse({'role': role})
            if role_spec:
                role_info.update(role_spec)
            data += self._display_role_info(role_info)
        self.pager(data)
    @with_collection_artifacts_manager
    def execute_verify(self, artifacts_manager=None):