Remove project_code filter from BuildSerializer

Removed project_code filter from BuildSerializer.

src/backend/InvenTree/build/serializers.py

@@ -164,17 +164,6 @@ class BuildSerializer(
         filter_name='project_code_detail',
     )
 
-    project_code = enable_filter(
-        FilterableIntegerField(
-            allow_null=True,
-            required=False,
-            label=_('Project Code'),
-            help_text=_('Project code for this build order'),
-        ),
-        True,
-        filter_name='project_code_detail',
-    )
-
     @staticmethod
     def annotate_queryset(queryset):
         """Add custom annotations to the BuildSerializer queryset, performing database queries as efficiently as possible.