[BUGFIX] Use `modTSconfig` for default language label, if set

Due to a wrong assignment, modSharedTSconfig is always used
to set the default language label in PageLayoutController, even if
modTSconfig is set.

modTSconfig is now used if possible.

Resolves: #75242
Releases: master, 7.6, 6.2
Change-Id: I517c03f02ffc8d05ed74a865517ee775e1542bfe
Reviewed-on: https://review.typo3.org/47371

Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>
Reviewed-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Tested-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>

typo3/sysext/backend/Classes/Controller/PageLayoutController.php

@@ -403,7 +403,7 @@ class PageLayoutController
         }
         // Setting alternative default label:
         if (($this->modSharedTSconfig['properties']['defaultLanguageLabel'] || $this->modTSconfig['properties']['defaultLanguageLabel']) && isset($this->MOD_MENU['language'][0])) {
-            $this->MOD_MENU['language'][0] = $this->modTSconfig['properties']['defaultLanguageLabel'] ? $this->modSharedTSconfig['properties']['defaultLanguageLabel'] : $this->modSharedTSconfig['properties']['defaultLanguageLabel'];
+            $this->MOD_MENU['language'][0] = $this->modTSconfig['properties']['defaultLanguageLabel'] ? $this->modTSconfig['properties']['defaultLanguageLabel'] : $this->modSharedTSconfig['properties']['defaultLanguageLabel'];
         }
         // Clean up settings
         $this->MOD_SETTINGS = BackendUtility::getModuleData($this->MOD_MENU, GeneralUtility::_GP('SET'), $this->moduleName);