[BUGFIX] Fix "No results" positioning in Live Search

The "No results found" alert is rendered in a flex-row container, which
caused a rendering bug where the alert box was stretched to a height of
100%, but its width is limited to its content. Use flex children
modifiers to ensure correct positioning.

Resolves: #103662
Releases: main, 12.4
Change-Id: I5b17950ca381fda841cd3a901d9f5e1a70e5562d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83919


Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>