Replaced the deprecated 'self::$container->get' with 'self::getContainer()->get' using rector

This change is made to comply with the new Symfony standards and to avoid deprecation warnings for future versions. The update touches various functionalities, including retrieving EntityManagerInterface instance and various service classes within the test files.

rector.php

@@ -27,6 +27,9 @@ return static function (RectorConfig $rectorConfig): void {
 
     // register a single rule
     $rectorConfig->rule(InlineConstructorDefaultToPropertyRector::class);
+
+    // part of the symfony 54 rules
+    $rectorConfig->rule(\Rector\Symfony\Symfony53\Rector\StaticPropertyFetch\KernelTestCaseContainerPropertyDeprecationRector::class);
     $rectorConfig->disableParallel();
 
     //define sets of rules