Add "edit" button to release blocks on Releases page

What does this MR do?

Adds an "edit" button to each release block on the Releases page that links to the Edit Release page that is being implemented in !18033 (merged) as part of #26016 (closed).

This MR also makes some improvements to the release block Jest test (release_block_spec.js).

This MR is dependent on this backend MR that adds the _links object to the API response that includes the link to the Edit Release page: !17858 (merged). However, this frontend MR can be safely merged before the !17858 (merged); if the _links property is missing in the API response, the "edit" button is not rendered.

Feature flag

The changes in this MR are hidden behind a release_edit_page feature flag, which is not enabled by default. This is the same feature flag used by the backend portions of this feature: !17858 (diffs).

Screenshots

Tooltip:

Responsive behavior: