outliner.delete - make errors from attempt to delete locked object less scary

Traceback errors give users an impression that some broke and maybe project now is in some invalid state and they should ctrl-z immediately, error reports are much more friendly.

Before - https://i.imgur.com/N4fUU1M.png
After - https://i.imgur.com/6On1Be0.png

src/bonsai/test/tool/test_blender.py

@@ -59,3 +59,47 @@ class TestSortPanelsForRegister(NewFile):
 
         with pytest.raises(AssertionError):
             subject.sort_panels_for_register(items, {"J": "A"})
+
+
+class TestBlenderErrorMessageExtraction(NewFile):
+    def test_extract_operator_reports(self) -> None:
+
+        ERROR_REPORTS = ["ERROR!!!\nERROR", "ERROR"]
+
+        class OBJECT_OT_test_fail_operator(bpy.types.Operator):
+            bl_idname = "object.test_fail_operator"
+            bl_label = "Test Fail Operator"
+
+            def execute(self, context):
+                self.report({"INFO"}, "Info message.")
+                subject.report_operator_errors(self, ERROR_REPORTS)
+                return {"FINISHED"}
+
+        bpy.utils.register_class(OBJECT_OT_test_fail_operator)
+
+        try:
+            bpy.ops.object.test_fail_operator()
+        except RuntimeError as e:
+            error_reports = subject.extract_error_reports(e)
+            assert error_reports == ERROR_REPORTS
+
+        bpy.utils.unregister_class(OBJECT_OT_test_fail_operator)
+
+    def test_ignore_actual_runtime_errors_from_operators(self) -> None:
+
+        class OBJECT_OT_test_fail_operator(bpy.types.Operator):
+            bl_idname = "object.test_fail_operator"
+            bl_label = "Test Fail Operator"
+
+            def execute(self, context):
+                raise RuntimeError("Intentional runtime error.")
+
+        bpy.utils.register_class(OBJECT_OT_test_fail_operator)
+
+        try:
+            bpy.ops.object.test_fail_operator()
+        except RuntimeError as e:
+            error_reports = subject.extract_error_reports(e)
+            assert error_reports == []
+
+        bpy.utils.unregister_class(OBJECT_OT_test_fail_operator)