add sys.getandroidapilevel

https://docs.python.org/3/library/sys.html#sys.getandroidapilevel

Author: guoci

stdlib/sys/__init__.pyi

@@ -366,6 +366,10 @@ if sys.version_info >= (3, 11):
     def exception() -> BaseException | None: ...
 
 def exit(status: _ExitCode = None, /) -> NoReturn: ...
+
+if sys.platform == "android":
+    def getandroidapilevel() -> int: ...
+
 def getallocatedblocks() -> int: ...
 def getdefaultencoding() -> str: ...