When iOS Safari goes to background, sound stops after a while and is not restored when reopening Safari

[waochi]

Godot version

3.3.4.stable

System information

iOS 15.0, safari

Issue description

If I put the safari process in the background (or put my iPhone to sleep) with sound playing, and wait for 30 seconds and then put Safari in the foreground again, there will be no sound at all.

Once this happens, sounds will not play unless reloading.
This problem does not occur on IOS 14 or lower.

Steps to reproduce

• Create a 2d scene
• Add AudioStreamPlayer node and Button node
• Run the game on safari(ios15) and play sound
• Put Safari process in the background and wait 30 seconds
• Put Safari in the foreground

Minimal reproduction project

audio_test.zip

[Calinou]

This was confirmed in https://godotforums.org/discussion/29734/html5-export-minimizing-app-on-ipad-causes-issues.