Sending a list of playback modes rather than a single one.

This is in order to have a fallback in case the requested mode is unsupported for the URL.

In this case - fallback to the next mode rather than showing a playback error.

This CL also includes file formatting of ReadAloudControllerUnitTest.java.

Bug: 412885365
Change-Id: I697a38cc63dafe52f9cf8a8a595ef9e958d62fed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6657988
Reviewed-by: Andrea Gomez <andreaxg@google.com>
Commit-Queue: Shlomi Ben Shimon <shlomib@google.com>
Cr-Commit-Position: refs/heads/main@{#1480439}