fix: remove webtransport from default transports

[2color]

Description

WebTransport is still not working reliably across different browsers. Moreover, the go-libp2p implementation needs to be updated to meet newer revisions of the spec.

As we discussed during Helia WG, the most sensible thing for now is to remove WebTransport from the default transports.

Related to https://github.com/libp2p/js-libp2p/issues/2572

Change checklist

• [ ] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation if necessary (this includes comments as well)
• [ ] I have added tests that prove my fix is effective or that my feature works

[2color]

@achingbrain Any thoughts on this?

[achingbrain]

This makes me a bit 😭 but I don't how else we can give users a good experience otherwise right now.