Show the search branch in the empty search state

The branch/tags/commit Switch selector is not shown in the 'Code' tab if there is no result.

branch/tags/commit Switch not shown(not expect):

branch/tags/commit Switch shown normally:

The following discussion from !28282 (merged) should be addressed:

• @pslaughter started a discussion: (+2 comments)

  praise: Nice catch for the empty use case! 💪

  suggestion: What do you think of handling this in a separate MR? We should probably get UX's opinion on this case and we also need to find a way to handle the duplicate code that's introduced. This will further delay this MR from getting merged, and I'd like for it to be merged soon 😄

  @leiminghany, could we remove the changes to this file and search_helper.rb and create a follow up issue for showing the branch in the empty search state?