[BUGFIX] Fix sprintf() PHP warning in FinisherOptionGenerator

User supplied strings must not be concatenated into the format
parameter of sprintf() as sequences like %s, or (more likely) %20S
(which is ' S' url escaped) may be contained and cause warnings
because sprintf() expects additional arguments in that case.

Streamline to always use the static '%s: "%s"' format instead.

Releases: main, 11.5, 10.4
Resolves: #96478
Change-Id: Ic3b09c6e1e7c617e78ea405289680bd78d0aab64
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72901
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benjamin Franzke <bfr@qbus.de>
Reviewed-by: Benjamin Franzke <bfr@qbus.de>

typo3/sysext/form/Classes/Domain/Configuration/FlexformConfiguration/Processors/FinisherOptionGenerator.php

@@ -90,10 +90,11 @@ public function __invoke(string $_, $__, array $matches)
         }
 
         if (empty($optionValue)) {
-            $elementConfiguration['label'] .= sprintf(' (%s: "%s")', $this->languageService->getLL('default'), $this->languageService->getLL('empty'));
-        } else {
-            $elementConfiguration['label'] .= sprintf(' (%s: "' . $optionValue . '")', $this->languageService->getLL('default'));
+            $optionValue = $this->languageService->getLL('empty');
+        } elseif (is_array($optionValue)) {
+            $optionValue = implode(',', $optionValue);
         }
+        $elementConfiguration['label'] .= sprintf(' (%s: "%s")', $this->languageService->getLL('default'), $optionValue);
 
         if (isset($elementConfiguration['config'])) {
             $elementConfiguration['config']['default'] = $optionValue;