multimedia/get_iplayer: Update to 3.30

ChangeLog:
https://github.com/get-iplayer/get_iplayer/wiki/release330to339#release330

• Fixed a bug that produced audio-only downloads for some programmes when FHD quality was requested but no 1080p video was available.
• Progress display for FHD downloads only now iterates towards a closer approximation of final file size. FHD file size estimates shown with --info remain very inaccurate.

PR: 264349
Reported by: jamie@catflap.org (maintainer)