Merge branch 'hotfix/fix_bug_when_musical_date_is_null' into develop

src/Service/OnChange/Organization/OnParametersChange.php

@@ -64,7 +64,7 @@ class OnParametersChange extends OnChangeDefault
         // La date de début d'activité change
         if (
             $context->previousData()
-            && $context->previousData()->getMusicalDate()->getTimestamp() !== $parameters->getMusicalDate()->getTimestamp()
+            && $context->previousData()->getMusicalDate()?->getTimestamp() !== $parameters->getMusicalDate()?->getTimestamp()
         ) {
             $this->onMusicalDateChange(
                 $parameters,