[BUGFIX] Correct typos in AbstractPlugin::pi_list_browseresults()

* Add a forgotten '$'
* Encapsulate ternary condition before concatenating strings

Resolves: #81153
Releases: master, 8.7
Change-Id: I0e180d2115435f0f41fb7b89862ff5d868c4dbd5
Reviewed-on: https://review.typo3.org/52724


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Jan Helke <typo3@helke.de>
Tested-by: Jan Helke <typo3@helke.de>