Cleanup dependencies (part 4) (#8468)

Follow-up to #8425 . Final part - adds the CI check.

Release Notes:
- N/A

crates/assistant/Cargo.toml

@@ -13,20 +13,17 @@ doctest = false
 ai.workspace = true
 anyhow.workspace = true
 chrono.workspace = true
-client.workspace = true
 collections.workspace = true
 editor.workspace = true
 fs.workspace = true
 futures.workspace = true
 gpui.workspace = true
 indoc.workspace = true
-isahc.workspace = true
 language.workspace = true
 log.workspace = true
 menu.workspace = true
 multi_buffer.workspace = true
 ordered-float.workspace = true
-parking_lot.workspace = true
 project.workspace = true
 regex.workspace = true
 schemars.workspace = true