Simplify add reference image size implementation and fix segfaulting tests

Previously, there was a dance between invoke, execute, and draw. This
can probably be resolved, but is a high-risk for undo bugs. This
simplifies the logic flow to just a traditional _invoke -> _execute.

I add a new feature test to at least make sure it does something, and
this also fixes the segfault in tool tests as it no longer requires the
launching of the file browser.

src/bonsai/test/bim/feature/drawing.feature

@@ -3,12 +3,6 @@ Feature: Drawing
 
 Scenario: Duplicate drawing
     Given an empty IFC project
-    And I add a cube
-    And the object "Cube" is selected
-    And I look at the "Class" panel
-    And I set the "Products" property to "IfcElement"
-    And I set the "Class" property to "IfcWall"
-    And I click "Assign IFC Class"
     And I save IFC project
     And I look at the "Drawings" panel
     And I click "IMPORT"
@@ -315,3 +309,10 @@ Scenario: Create sheet - with a drawing added to it
     And I click "IMAGE_PLANE"
     When I click "OUTPUT"
     Then the file "{ifc_dir}/sheets/A01 - UNTITLED.svg" should contain "IfcWall"
+
+Scenario: Add reference image
+    Given an empty IFC project
+    And I save IFC project
+    When I press "bim.add_reference_image(filepath='{cwd}/test/files/image.jpg')"
+    Then the object "IfcAnnotation/image" exists
+    And the object "IfcAnnotation/image" dimensions are "1.0,0.565,0."

src/bonsai/test/tool/test_drawing.py

@@ -938,7 +938,7 @@ class TestAddReferenceImage(NewFile):
 
         obj = bpy.data.objects["IfcAnnotation/image"]
         assert obj is not None
-        assert tool.Cad.are_vectors_equal(obj.dimensions, Vector((3.53982, 2.0, 0.0)))
+        assert tool.Cad.are_vectors_equal(obj.dimensions, Vector((1.0, 0.565, 0.0)))
 
         material = obj.active_material
         assert material