[ty] Disambiguate classes that live in different modules but have the same fully qualified names (#20756)

## Summary

Even disambiguating classes using their fully qualified names is not
enough for some diagnostics. We've seen real-world examples in the
ecosystem (and https://github.com/astral-sh/ruff/pull/20368 introduces
some more!) where two types can be different, but can still have the
same fully qualified name. In these cases, our disambiguation machinery
needs to print the file path and line number of the class in order to
disambiguate classes with similar names in our diagnostics.

Helps with https://github.com/astral-sh/ty/issues/1306

## Test Plan

Mdtests

crates/ty_python_semantic/resources/mdtest/diagnostics/same_names.md

@@ -61,6 +61,35 @@ class DataFrame:
     pass
 ```
 
+## Class from different module with the same qualified name
+
+`package/__init__.py`:
+
+```py
+from .foo import MyClass
+
+def make_MyClass() -> MyClass:
+    return MyClass()
+```
+
+`package/foo.pyi`:
+
+```pyi
+class MyClass: ...
+```
+
+`package/foo.py`:
+
+```py
+class MyClass: ...
+
+def get_MyClass() -> MyClass:
+    from . import make_MyClass
+
+    # error: [invalid-return-type] "Return type does not match returned value: expected `package.foo.MyClass @ src/package/foo.py:1`, found `package.foo.MyClass @ src/package/foo.pyi:1`"
+    return make_MyClass()
+```
+
 ## Enum from different modules
 
 ```py