Update typing_extensions imports in third-party stubs (#11245)

stubs/pyasn1/pyasn1/__init__.pyi

@@ -1,3 +1,3 @@
-from typing_extensions import Final
+from typing import Final
 
 __version__: Final[str]

stubs/pyasn1/pyasn1/compat/integer.pyi

@@ -1,4 +1,4 @@
-from typing_extensions import Literal
+from typing import Literal
 
 implementation: str
 null: Literal[b""]

stubs/pyasn1/pyasn1/compat/octets.pyi

@@ -1,5 +1,4 @@
-from typing import TypeVar
-from typing_extensions import Literal
+from typing import Literal, TypeVar
 
 _T = TypeVar("_T")
 

stubs/pyasn1/pyasn1/type/base.pyi

@@ -1,6 +1,5 @@
 from _typeshed import Incomplete, Unused
-from typing import NoReturn, type_check_only
-from typing_extensions import final
+from typing import NoReturn, final, type_check_only
 
 from pyasn1.type import constraint, namedtype
 from pyasn1.type.tag import TagSet