Added an option to use the native fullscreen of a browser in webapps

[JuggerbAUT]

This PR introduces native web fullscreen support to provide a more immersive video playback experience in web browsers.

Problem

Currently, the fullscreen mode in chewie on web has some limitations:

• Browser UI remains visible: When entering fullscreen, browser elements like the address bar and tabs are still visible, which is not a true fullscreen experience.
• Constrained by parent containers: in a width restriced webapp the fullscreen mode of the player is also restricted -> removing this restriction with a variable set in a provider leads to problems with the player notifier

Solution

useNativeWebFullscreen flag: A new boolean flag, useNativeWebFullscreen, has been added to ChewieController. This flag is true by default. When set to false, it reverts to the original fullscreen behavior.

[codecov]

Codecov Report

❌ Patch coverage is 16.66667% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 43.71%. Comparing base (d228479) to head (8aecf50).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
lib/src/chewie_player.dart	20.00%	4 Missing ⚠️
...src/helpers/fullscreen_controller_unsupported.dart	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #936      +/-   ##
==========================================
- Coverage   43.84%   43.71%   -0.13%     
==========================================
  Files          21       22       +1     
  Lines        1601     1608       +7     
==========================================
+ Hits          702      703       +1     
- Misses        899      905       +6     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.