[BUGFIX] Avoid SQL error in indexed search administration

The field "uid" is never fetched, so no count() is possible
in the DB count query.

Resolves: #85252
Releases: master, 9.3
Change-Id: I9a3f1cb13bf20dcbe4bfb5451afd465e5981ecb4
Reviewed-on: https://review.typo3.org/57634


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Jörg Bösche <typo3@joergboesche.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>