Do not report all open buffers to new instances of the same language
server, as they can respond with ~spurious errors.

This regressed in  https://github.com/zed-industries/zed/pull/34142

Closes https://github.com/zed-industries/zed/issues/35017

Release Notes:

- Fixed Zed overly notifying language servers about open buffers, which
could've resulted in confusing errors in multi-language projects (in
e.g. Go).