refactor: adds category to flash messages

app/utils/flash_message.py

@@ -1,4 +1,8 @@
+from app.utils.flash_message_category import FlashMessageCategory
+
+
 class FlashMessage:
-  def __init__(self, message, alertType):
+  def __init__(self, message, alertType, category: FlashMessageCategory = None):
     self.message = message
-    self.alertType = alertType
+    self.alertType = alertType
+    self.category = category