PY-44714 PyTypedDictInspection: don't register problem with None

Fix false positive with None as TypedDict value type
close #1452

GitOrigin-RevId: 7c02d8928f2e9ef3612aaf69d6daeb5a1b71cb95

python/python-psi-impl/src/com/jetbrains/python/inspections/PyTypedDictInspection.kt

@@ -278,7 +278,7 @@ class PyTypedDictInspection : PyInspection() {
      * Checks that [expression] with [strType] name is a type
      */
     private fun checkValueIsAType(expression: PyExpression?, strType: String?) {
-      if (expression !is PyReferenceExpression && expression !is PySubscriptionExpression || strType == null) {
+      if (expression !is PyReferenceExpression && expression !is PySubscriptionExpression && expression !is PyNoneLiteralExpression || strType == null) {
         registerProblem(expression, PyPsiBundle.message("INSP.typeddict.value.must.be.type"), ProblemHighlightType.WEAK_WARNING)
         return
       }

python/testSrc/com/jetbrains/python/inspections/PyTypedDictInspectionTest.java

@@ -300,6 +300,16 @@ public class PyTypedDictInspectionTest extends PyInspectionTestCase {
                          "    return movie[<warning descr=\"TypedDict key must be a string literal; expected one of ('name', 'year')\">key</warning>]"));
   }
 
+  // PY-44714
+  public void testNoneAsType() {
+    runWithLanguageLevel(
+      LanguageLevel.getLatest(),
+      () -> doTestByText("from typing import TypedDict\n" +
+                         "class X(TypedDict):\n" +
+                         "    n: None\n" +
+                         "Y = TypedDict('Y', {'n': None})\n"));
+  }
+
   @NotNull
   @Override
   protected Class<? extends PyInspection> getInspectionClass() {