[keyserver][web] Use unique filename for each prod olm.wasm asset

Summary: More context in ENG-3322. Basically we started seeing an issue after updating Olm where the old version was still in cache. This is "by design" – keyserver serves all prod assets as immutable to improve performance. For this to work, we need to make sure each prod asset has a unique filename.

Test Plan: Test both dev and prod, open up Chrome Dev Tools network tab (while web is logged out) and confirm olm.wasm was loaded correctly

Reviewers: atul, michal, ginsu

Reviewed By: atul

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D7068