[BUGFIX] Set correct default connection charset "utf8"

Resolves: #84180
Releases: master, 8.7
Change-Id: Id868d3f379d131c3a51e039e6a862e4dcabf2fda
Reviewed-on: https://review.typo3.org/56081
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>

typo3/sysext/core/Classes/Database/ConnectionPool.php

@@ -124,7 +124,7 @@ protected function getDatabaseConnection(array $connectionParams): Connection
     {
         // Default to UTF-8 connection charset
         if (empty($connectionParams['charset'])) {
-            $connectionParams['charset'] = 'utf-8';
+            $connectionParams['charset'] = 'utf8';
         }
 
         // Force consistent handling of binary objects across datbase platforms