Playing voicemail in the background

> If the user navigates out and back to the room, the recordings should simply stop playing and return to their default state.

Re: last one, I'd argue that a user press "play" on a voice message and then expects it to keep playing in the background, to multi-task and "play incoming voicemail", of sorts.

Though that would need a new design and behaviour for it (and so a new issue), maybe it could re-use the same modals as VoIP? And then show a mini-player in the corner of the screen, thus place it orthogonally alongside other "voice" or "multimedia connectivity"-related things.

__Originally posted by @ShadowJonathan in https://github.com/vector-im/element-web/issues/17439#issuecomment-878256039__

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Basically; have it be possible to stack up incoming played messages, and/or play audio from another room, and have a voip-like tile sit in the bottom right corner with media controls.