fix: Force using mcap polyfill on EOS browsers (#4630)

The MCap API on the EOS set-top boxes is rather buggy thus we're relying
on the polyfill instead.

lib/polyfill/media_capabilities.js

@@ -43,6 +43,7 @@ shaka.polyfill.MediaCapabilities = class {
         !shaka.util.Platform.isPS5() &&
         !shaka.util.Platform.isWebOS() &&
         !shaka.util.Platform.isTizen() &&
+        !shaka.util.Platform.isEOS() &&
         navigator.mediaCapabilities) {
       shaka.log.info(
           'MediaCapabilities: Native mediaCapabilities support found.');