assistant: Add Bedrock support (#21092)

Closes #16544

Release Notes:

- Added support for AWS Bedrock to the Assistant.

---------

Co-authored-by: Marshall Bowers <git@maxdeviant.com>
Co-authored-by: Anthony <anthony@zed.dev>
Co-authored-by: Anthony Eid <hello@anthonyeid.me>

crates/zed/src/zed.rs

@@ -4214,6 +4214,7 @@ mod tests {
 
             app_state.languages.add(markdown_language());
 
+            gpui_tokio::init(cx);
             vim_mode_setting::init(cx);
             theme::init(theme::LoadThemes::JustBase, cx);
             audio::init((), cx);