core tests - more readable errors

E.g. it shows now:
AttributeError: Interface 'bonsai.core.tool.Drawing' has no attribute 'weird_method'.

Instead of:
Prophecy <class 'abc.Drawing'> has no attribute weird_method

src/bonsai/bonsai/core/tool.py

@@ -28,7 +28,9 @@ from typing import Optional
 class Interface(abc.ABC): pass
 def interface(cls):
     attrs = {n: classmethod(abc.abstractmethod(f)) for n, f in inspect.getmembers(cls, predicate=inspect.isfunction)}
-    return type(cls.__name__, (Interface, cls), attrs)
+    new_cls = type(cls.__name__, (Interface, cls), attrs)
+    new_cls.__original_qualname__ = cls.__module__ + "." + cls.__qualname__
+    return new_cls
 
 
 # ############################################################################ #

src/bonsai/test/core/bootstrap.py

@@ -272,7 +272,7 @@ class Prophecy:
 
     def __getattr__(self, attr: str):
         if not hasattr(self.subject, attr):
-            raise AttributeError(f"Prophecy {self.subject} has no attribute {attr}")
+            raise AttributeError(f"Interface '{self.subject.__original_qualname__}' has no attribute '{attr}'.")
 
         # It also returns `Any` but it only happens during `subject.xxx` call.
         def decorate(*args: Any, **kwargs: Any) -> Self:
@@ -317,7 +317,7 @@ class Prophecy:
                 raise Exception(f"Called {count}: {prediction}")
         else:
             if prediction["call"] not in self.calls:
-                error_msg = f"{self.subject} was not called with {prediction['call']['name']}:\n - {prediction}"
+                error_msg = f"Interface '{self.subject.__original_qualname__}' was not called with {prediction['call']['name']}:\n - {prediction}"
 
                 # Print all unprocessed calls if pytest was started in verbose mode.
                 if "-v" in sys.argv or "-vv" in sys.argv: