Add notice of requesting source code in media and media swcodec

Flag: EXEMPT license change for b/418865751
Bug: 418865751
Test: presubmits
Test: lunch husky-trunk_staging-eng && m, an extra line is added at the top of NOTICE.html file in NOTICE.html.gz
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:6076b226064bea51f93b1494d9782e4c56412662)
Merged-In: Id9c729d8d6d1b00414ffa5364929315da7b0d55a
Change-Id: Id9c729d8d6d1b00414ffa5364929315da7b0d55a