Misc ws fixes

[jordy25519]

Motivation

Some small fixes found while going through the ws code

• to_raw_valuehelper is slightly more efficient
• ws ping frames are handled transparently by tungstenite

Solution

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[DaniPopes]

I don't believe to_raw_value and RawValue::from_string are equivalent, see failing tests in CI: https://github.com/gakonst/ethers-rs/actions/runs/4842761312/jobs/8748645910?pr=2389
Can you please check again?

[jordy25519]

I don't believe to_raw_value and RawValue::from_string are equivalent, see failing tests in CI: https://github.com/gakonst/ethers-rs/actions/runs/4842761312/jobs/8748645910?pr=2389 Can you please check again?

needed to remove the escape \ chars, checked tests are passing now

[DaniPopes]

Right, thanks!