[BUGFIX] Avoid invalid orderBy for count query in EXT:reactions

Avoid an exception if using PostgreSQL because there
must not be a orderBy part if building a count query.
PostgreSQL is here quite strict.

Additionally, ensuring determinisic ordering is done
a long the way as a side change.

Resolves: #99257
Releases: main
Change-Id: Icec779f0e0b2949c74f8c7fee704305d7af9f132
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76890


Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Georg Ringer <georg.ringer@gmail.com>