[TASK] Raise typo3fluid/fluid:^2.7.3

This patch level release comes with a set
of minor bug fixes and should be the minimum
version for TYPO3 v12 from now on.

> composer req typo3fluid/fluid:^2.7.3

Resolves: #100243
Releases: main
Change-Id: Id57b8b7f0a30211fe90d09b854475fceda58901e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78206


Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>