Enable `strict_equality` mypy option

Also fix the following mypy error:

```
lib/galaxy/util/path/__init__.py:247: error: Non-overlapping equality check (left operand type: "struct_passwd", right operand type: "str")  [comparison-overlap]
            or (file_owner == username and owner_permissions >= 4)
```

lib/galaxy/util/path/__init__.py

@@ -244,7 +244,7 @@ def __path_permission_for_user(path: GenericPath, username: str) -> bool:
     other_permissions = int(oct_mode[-1])
     if (
         other_permissions >= 4
-        or (file_owner == username and owner_permissions >= 4)
+        or (file_owner.pw_name == username and owner_permissions >= 4)
         or (username in group_members and group_permissions >= 4)
     ):
         return True

mypy.ini

@@ -6,6 +6,7 @@ exclude = lib/galaxy/tools/bundled|test/functional
 pretty = True
 no_implicit_reexport = True
 no_implicit_optional = True
+strict_equality = True
 
 # green list - work on growing these please!
 [mypy-galaxy.util.compression_utils]