Update tungstenite to 0.26

[coolreader18]

Description of Changes

Tungstenite 0.26 switches its Message to use Bytes instead of Vec<u8> for the payload, meaning we can now send messages without making a duplicate allocation for every client.

Expected complexity level and risk

2: updating a dependency, but it's pretty low risk.

Testing

n/a - general optimization

[coolreader18]

This pulls in rand 0.9 now, but I can make a followup to deduplicate that dependency.

[Centril]

This pulls in rand 0.9 now, but I can make a followup to deduplicate that dependency.

Sounds good. Seems like zerocopy and other deps were duplicated as well, if you want to investigate in follow ups.