Update provided type for typing.Callable (PY-28177)

Use custom type inheriting class-like type to suppress `Callable[...]` warnings.
Remove some checks against `Callable` in type checker because they are processed below when matching callable types.
Update custom type to detemine ability to call from the name as well.

python/testSrc/com/jetbrains/python/inspections/Py3UnresolvedReferencesInspectionTest.java

@@ -220,6 +220,11 @@ public class Py3UnresolvedReferencesInspectionTest extends PyInspectionTestCase
     doTest();
   }
 
+  // PY-28177
+  public void testTypingOpaqueNameDunderGetItem() {
+    doTest();
+  }
+
   // PY-21655
   public void testUsageOfFunctionDecoratedWithAsyncioCoroutine() {
     doMultiFileTest("a.py");