Hide mirror list table if the count is zero in project mirror settings

Proposal

Proposal from @yo's MR: When the project mirror settings is empty, hide the mirror list table.

When there are no mirrored repositories, display an empty state for the table.

• Single column: Mirrored repositories(0)
• Empty state message: There are currently no mirrored repositories.

Note: Not going with the yellow alert as the empty state because that is not the intended purpose of the alert.

Before	After

Details

There's a stalled open Community contribution MR in: !54230 (closed)

We can pick it up and take it to completion. Make sure to check the review comments already in that MR, too.