[iOS] Youtube background play does not work

[iccub]

Description:

Steps to Reproduce

1. Enable background playback
2. Visit youtube
3. Put Brave to background

Actual result:

Expected result:

Reproduces how often: [Easily reproduced, Intermittent Issue]

Brave Version:

• Can you reproduce this issue with the most recent build from TestFlight?
• Can you reproduce this issue with the previous version of the current build from TestFlight?
• Can you reproduce this issue with the current build from AppStore?

Device details:

Website problems only:

• Does the issue resolve itself when disabling Brave Shields?
• Is the issue reproducible on the latest version of Mobile Safari?

Additional Information