Remove note about the`release_asset_link_editing` feature flag
What does this MR do?
Undoes (most of) the changes made in !29795 (merged).
!29795 (merged) was put together when we thought that this feature wouldn't make the %12.10 release cutoff, so we added this note to allow self-managed users to enable this feature.
This feature did end up making %12.10, so this note is unnecessary.
Related to: #9427 (closed)