Drop browser support for AI integrations

[nicohrubec]

This has very low usage but comes with some architectural pain points so we have decided to drop our AI integrations from the browser SDK:

• No longer export the AI integrations to the browser.
• Remove the AI integrations from the browser bundles.
• Move all of the helpers that the channel-based AI integrations in server-utils use to the server-utils package and update the imports.
• Remove the core instrumentations.

[linear-code]

JS-3075