[3.13] gh-132869: Fix crash in _PyObject_TryGetInstanceAttribute
          #133700
        
          
      
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This fixes a crash in
_PyObject_TryGetInstanceAttributedue to the use of_PyDictKeys_StringLookupon an unlocked dictionary that may be concurrently modified.The underlying bug was already fixed in 3.14 and the main branch.
(partially cherry picked from commit 1b15c89)