Fix panic when accessing `ssl://` Electrum server

[tnull]

Currently, we panic if we access an Electrum server using TLS as we switched to use aws-lc-rs as the go-to crypto provider for rustls, but none of the crates actually installs it.

IMO the right place to fix this would be in electrum-client which already assumes the use-rustls feature to use aws-lc-rs as a default provider in certain scenarios, just not the normal/default flow (see bitcoindevkit/rust-electrum-client#171).

In any case, if this isn't fixed upstream ASAP and a new release is out by the time of our next release, we'll need to make the corresponding changes here. Just documenting so we don't forget.