Hide mobile "Actions" label if no action buttons exist [RUN AS-IF-FOSS]

What does this MR do?

On the group members view, hides mobile "Actions" label if no action buttons exist.

In !46506 (merged) I hid the "Actions" column if there were no action buttons (Remove member, Resend invite, etc) to display. What I missed was that the "Actions" label still will display on mobile when it doesn't need to. This MR hides the "Actions" label on mobile if it doesn't need to be shown.

Screenshots (strongly suggested)

Before	After

Local testing

1. Create a group
2. Add a member to the group in "Group" -> "Members"
3. Create a subgroup under that group. "Group overview" -> "New subgroup"
4. Navigate to "Subgroup" -> "Members"
5. Resize the browser to mobile

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team