Fix right-aligned input icons (#30301)

Fix right-aligned input icons (#30301)

Fix regression from https://github.com/go-gitea/gitea/pull/30194 where
right-aligned items would not display correctly.

Before and After:

<img width="285" alt="Screenshot 2024-04-06 at 01 12 11"
src="https://github.com/go-gitea/gitea/assets/115237/f9168db5-0f69-4b5d-ba17-b60145ac4a09">
<img width="285" alt="Screenshot 2024-04-06 at 01 11 49"
src="https://github.com/go-gitea/gitea/assets/115237/639ab6ed-d018-4e3a-9980-1f079e4ebe9d">

Frontpage search tweaked to accommodate (which was the reason for the
changes that broken above):

<img width="445" alt="Screenshot 2024-04-06 at 01 11 34"
src="https://github.com/go-gitea/gitea/assets/115237/1919220b-390e-463a-8e3d-33a3556bf111">
<img width="438" alt="Screenshot 2024-04-06 at 01 11 39"
src="https://github.com/go-gitea/gitea/assets/115237/fd94f8e4-1d56-4b04-99e3-1cd240bd7ab4">