remove ExportIFCBase as it's unused

src/bonsai/bonsai/bim/module/project/operator.py

@@ -1290,7 +1290,7 @@ class SelectLinkHandle(bpy.types.Operator):
         return {"FINISHED"}
 
 
-class ExportIFCBase:
+class ExportIFC(bpy.types.Operator):
     bl_idname = "bim.save_project"
     bl_label = "Save IFC"
     bl_options = {"REGISTER", "UNDO"}
@@ -1412,10 +1412,6 @@ class ExportIFCBase:
         return "Save the IFC file.  Will save both .IFC/.BLEND files if synced together"
 
 
-class ExportIFC(ExportIFCBase, bpy.types.Operator):
-    pass
-
-
 class LoadLinkedProject(bpy.types.Operator):
     bl_idname = "bim.load_linked_project"
     bl_label = "Load a project for viewing only."