Remove outdated TODO

Summary:
I was doing a quick search for `TODO(T101303314)` occurences to make sure my
cleanups are finished from the `__getitem__` -> `Subscript` transition, and I
found this one which was actually fixed a couple weeks ago when I finished the
`__setitem__` logic, I just forgot to delete the TODO in the test.

Reviewed By: alexkassil

Differential Revision: D57627449

fbshipit-source-id: 8fb8a46847faeac22c351dbc89abd43cab880b36

source/analysis/test/uninitializedLocalCheckTest.ml

@@ -258,7 +258,6 @@ let test_simple =
         y = None
     |}
            ["Uninitialized local [61]: Local variable `y` is undefined, or not always defined."];
-      (* TODO(T101303314) Validate use of uninitialized locals in subscript assignment targets *)
       labeled_test_case __FUNCTION__ __LINE__
       @@ assert_uninitialized_errors
            {|