fix: Fix MediaCapabilities polyfill on Safari
fix: Fix MediaCapabilities polyfill on Safari

Fixes #3696
Fixes #3530

Change-Id: I2f2e248c9001e10013eb4b03af6b9ef49f28dc6c

tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,shaka-project/shaka-player