External Media: highlighting media discrepancies

### Impacted plugin

Jetpack

### What

When using the External Media modal, there seems to be 2 different types of focus on media. They can prove a bit confusing since there is little difference between the 2.

### How

Here is a screencast outlining the differences:

https://user-images.githubusercontent.com/426388/187930118-e149d85f-e67e-4588-a28d-2660686bce62.mov

Start with the External Media modal and review the linked screencast to reproduce and distinguish the two reported media focus states. Confirm the relevant frontend entry point and document a clear expected difference or consistent behavior so the discrepancy is no longer confusing.

Written by the indexing model from the issue text.