refactor: refactor unnecessary else / elif when if block has a return statement (#5735)

The use of `else` or `elif` becomes redundant and can be dropped if the last statement under the leading `if` / `elif` block is a `return` statement.
In the case of an `elif` after `return`, it can be written as a separate `if` block.
For `else` blocks after `return`, the statements can be shifted out of `else`. Please refer to the examples below for reference.

Refactoring the code this way can improve code-readability and make it easier to maintain.

Co-authored-by: deepsource-autofix[bot] <62050782+deepsource-autofix[bot]@users.noreply.github.com>

InvenTree/stock/models.py

@@ -1842,9 +1842,8 @@ class StockItem(InvenTreeBarcodeMixin, InvenTreeNotesMixin, MetadataMixin, commo
             self.delete()
 
             return False
-        else:
-            self.save()
-            return True
+        self.save()
+        return True
 
     @transaction.atomic
     def stocktake(self, count, user, notes=''):
@@ -2234,8 +2233,7 @@ class StockItemTracking(models.Model):
         """Return label."""
         if self.tracking_type in StockHistoryCode.keys():
             return StockHistoryCode.label(self.tracking_type)
-        else:
-            return self.title
+        return self.title
 
     tracking_type = models.IntegerField(
         default=StockHistoryCode.LEGACY,