Crash because of resource leak

[lhns]

Hello!
I noticed when calling predict multiple times, after some time further prediction processes just crash.
It seems to be caused by a resource leak because the InferenceSession is never released (session.release();) in https://github.com/diffusionstudio/vits-web/blob/main/src/inference.ts#L72
I've noticed though, that it makes prediction even slower.
I did a quick hack, where I cache the session and that improved the performance quite a bit.
Sadly I don't have time to implement a proper fix at the moment.