Fix issue with search from FAB

[micahmo]

Pull Request Description

This PR fixes an issue where the comment search function could not be invoked if it were the primary (single press) FAB button.

Issue Being Fixed

Issue Number: See #1306 (comment)

Screenshots / Recordings

qemu-system-x86_64_THkK12BRvJ.mp4

Checklist

• Did you update CHANGELOG.md?
• Did you use localized strings where applicable?
• Did you add semanticLabels where applicable for accessibility?

[hjiangsu]

LGTM!

On a side note, I would like to eventually refactor our handling of override actions (it's getting a bit complicated 😅)

override: singlePressAction == PostFabAction.backToTop
? () => {
      _itemScrollController.scrollTo(
        index: 0,
        duration: const Duration(milliseconds: 500),
        curve: Curves.easeInOut,
      )
    }
: singlePressAction == PostFabAction.changeSort
    ? () => showSortBottomSheet(context, state)
    : singlePressAction == PostFabAction.replyToPost
        ? () => replyToPost(context, postLocked: postLocked)
        : singlePressAction == PostFabAction.search
            ? () => startCommentSearch(context)
            : null),

[micahmo]

I would like to eventually refactor our handling of override actions (it's getting a bit complicated 😅)

Totally agreed, that's exactly why this got missed.