Podcasts volume stays muted after ending a phone call

When you have a radio station playing on the Librem 5 Linux phone, and you receive a phone call, the following happens:

• When the phone is ringing, the volume of the radio station playing is lowered
• When you answer the phone call, the volume of the radio is muted, but it keeps playing (silently)
• When you end the phone call, the volume of the radio station stays muted and the station keeps playing (silently)

Expected behavior:

• When you end the phone call, the volume of the radio station switches back to the volume level it had before the phone was ringing, so you can continue listening to the radio without having to manually put the volume for Shortwave up from the silent (muted) level.

Probably related to #583 (closed).

Using Shortwave flatpak 3.2.0 from Flathub.