refactor(Trim Reblogs): Use `updatePostOnPage` util

### Description

I haven't checked if this makes any functional difference (if it did, it would be in scrolling away from and then back to a trimmed post with endless scrolling enabled, or perhaps in enabling trimming the same post multiple times), but we can probably use the `updatePostOnPage` util function in Trim Reblogs instead of manually removing trail dom elements.