[BUGFIX] Use json_encode instead of implode

To ensure unique identifiers for query entries the
backtrace is considered as part of the hash. As the
backtrace is multidimensional, stringification is no
longer done by using implode.

Resolves: #90449
Releases: master, 9.5
Change-Id: I920591c8c3df99aea5a2362c416e938b425e32a3
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63351


Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>