[BUGFIX] Adopt return type of CommandUtility::exec()

Allow the valid return type false which is returned by the function
exec on failure.

Resolves: #103778
Releases: main, 12.4
Change-Id: I8f0391efb6f890ebc0095ddb8a1f93ee9c36e18c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/84135


Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>
Tested-by: Benjamin Franzke <ben@bnf.dev>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>

typo3/sysext/core/Classes/Utility/CommandUtility.php

@@ -82,7 +82,7 @@ class CommandUtility
      *
      * Needs to be central to have better control and possible fix for issues
      */
-    public static function exec(string $command, ?array &$output = null, int &$returnValue = 0): string
+    public static function exec(string $command, ?array &$output = null, int &$returnValue = 0): string|false
     {
         return exec($command, $output, $returnValue);
     }