Allow boosting own follower-only posts directly with repost button

[tibequadorian]

Pitch

Since #4944 it's possible to set the visibility for boosts to something else than public so theoretically it should be possible to boost my own follower-only posts with follower-only visibility.

As of now, follower-only posts cannot be boosted at all because Tuskys UI does not allow it and shows a lock icon.

EDIT: They can be boosted through the three dot menu but it's not intuitive and should be possible with the repost button.

Motivation

Boosting my own follower-only posts to its original audience is a feature of Mastodon.

Better UI/UX

[connyduck]

It is possible, own followers-only posts have "Boost to original audience" in the three dot menu. But yeah it is not pretty.