total fee updates when a case fee is deleted

modules/opencase_cases/src/Entity/OCCase.php

@@ -227,6 +227,11 @@ class OCCase extends RevisionableContentEntityBase implements OCCaseInterface
     $this->save();
   }
 
+  public function subtractFromTotalFee(string $amountToSubtract): void {
+    $this->set('total_fee', $this->total_fee->value - $amountToSubtract);
+    $this->save();
+  }
+
   /**
    * {@inheritdoc}
    */