Bug 1787402 - explicitly reject the type if the process doesn't support that...

Bug 1787402 - explicitly reject the type if the process doesn't support that specific track before receving the support information from remote processes. r=azebrowski

We determine if a type is supported by checking the support information sent from remote processes.

If we haven't received that infermation, what we did before is, simply guess the remote process supports that type, and then try to create a real decoder in the remote process if possible.

However, as now we restrict certain processes can only support certain tracks. We can do that check earlier to eliminate an impossible case. Eg. requesting a video decoder to a process which only supports audio decoding.

Differential Revision: https://phabricator.services.mozilla.com/D155747