Issue #18520: Fix _PyDict_GetItemId(), suppress _PyUnicode_FromId() error

As PyDict_GetItem(), _PyDict_GetItemId() suppresses all errors that may occur,
for historical reasons.
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 36c710e..e0cb8ac 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2684,8 +2684,10 @@
 {
     PyObject *kv;
     kv = _PyUnicode_FromId(key); /* borrowed */
-    if (kv == NULL)
+    if (kv == NULL) {
+        PyErr_Clear();
         return NULL;
+    }
     return PyDict_GetItem(dp, kv);
 }