Remove unreferenced dev dependencies (#51093)

This will help with test times (in some cases), as nextest cannot figure
out whether a given rdep is actually an alive edge of the build graph

Closes #ISSUE

Before you mark this PR as ready for review, make sure that you have:
- [ ] Added a solid test coverage and/or screenshots from doing manual
testing
- [ ] Done a self-review taking into account security and performance
aspects
- [ ] Aligned any UI changes with the [UI
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)

Release Notes:

- N/A

crates/copilot/Cargo.toml

@@ -52,14 +52,10 @@ workspace.workspace = true
 async-std = { version = "1.12.0", features = ["unstable"] }
 
 [dev-dependencies]
-client = { workspace = true, features = ["test-support"] }
-clock = { workspace = true, features = ["test-support"] }
 collections = { workspace = true, features = ["test-support"] }
-ctor.workspace = true
 editor = { workspace = true, features = ["test-support"] }
 fs = { workspace = true, features = ["test-support"] }
 gpui = { workspace = true, features = ["test-support"] }
-http_client = { workspace = true, features = ["test-support"] }
 indoc.workspace = true
 language = { workspace = true, features = ["test-support"] }
 lsp = { workspace = true, features = ["test-support"] }