🎨(backend) simplify boolean comparisons by using opposite operators

Replace inverted boolean comparisons (not ... ==) with direct opposite
operators (!=) to improve code readability and reduce unnecessary
complexity in conditional statements.

src/backend/core/api/serializers.py

@@ -42,7 +42,7 @@ class ResourceAccessSerializerMixin:
                 data.get("role") == models.RoleChoices.OWNER
                 and not self.instance.resource.is_owner(user)
                 or self.instance.role == models.RoleChoices.OWNER
-                and not self.instance.user == user
+                and self.instance.user != user
             )
         ) or (
             # Create

src/backend/core/migrations/0014_room_pin_code.py

@@ -17,7 +17,7 @@ def generate_pin_for_rooms(apps, schema_editor):
     def generate_pin_code():
         while True:
             pin_code = str(secrets.randbelow(10 ** length)).zfill(length)
-            if not pin_code in existing_pins:
+            if pin_code not in existing_pins:
                 return pin_code
 
     for room in rooms_without_pin_code:

src/backend/core/recording/event/parsers.py

@@ -123,7 +123,7 @@ class MinioParser:
                 f"Invalid bucket: expected {self._bucket_name}, got {event_data.bucket_name}"
             )
 
-        if not event_data.filetype in self._allowed_filetypes:
+        if event_data.filetype not in self._allowed_filetypes:
             raise InvalidFileTypeError(
                 f"Invalid file type, expected {self._allowed_filetypes},"
                 f"got '{event_data.filetype}'"