Add type stub for sys.getandroidapilevel (#14936)

Co-authored-by: Alex Waygood <[email protected]>

Author: guoci

stdlib/sys/__init__.pyi

@@ -373,6 +373,10 @@ if sys.version_info >= (3, 11):
     def exception() -> BaseException | None: ...
 
 def exit(status: _ExitCode = None, /) -> NoReturn: ...
+
+if sys.platform == "android":  # noqa: Y008
+    def getandroidapilevel() -> int: ...
+
 def getallocatedblocks() -> int: ...
 def getdefaultencoding() -> str: ...