fix(FEC-10227): advanced captions setting window cut when opened in floating player

[yairans]

Description of the Changes

Issue: When the player is small (<= 480px), both language menu and cvaa are opened as an overlay in the overlay-portal. This causes 2 issues:

1. overlay.position: relative is inappropriate (pushes the bottom side panel up)
2. componentDidUnmount of the language menu is running after componentDidMount of the cvaa, and removing a necessary player class (overlay-active. sooverlay-portal.pointer-event remains none)

Solution:

1. change to overlay.position: absolute
2. delay the componentDidMount by timeout

CheckLists

• changes have been done against master branch, and PR does not conflict
• new unit / functional tests have been added (whenever applicable)
• test are passing in local environment
• Travis tests are passing (or test results are not worse than on master branch :))
• Docs have been updated