Deprecate SHOW and HIDE flag annotation

The usage of SHOW and HIDE flags was broken for some time, until its usage was removed recently. As those flags don't have any effect anymore when used via InputMethodManager, adding deprecation notice to them, to make developers aware.

Bug: 322992891
Test: None, deprecation only
Flag: android.view.inputmethod.deprecate_input_method_show_hide_flags
FCRS_CODE : mdem7kkcfrnse5

Change-Id: I7747d3317dee302569c22900e83435597c2c8744