Remove test-support feature from auto_update's gpui dep (#31147)

Fixes `cargo run` on main.

Release Notes:

- N/A

crates/auto_update/Cargo.toml

@@ -16,7 +16,7 @@ doctest = false
 anyhow.workspace = true
 client.workspace = true
 db.workspace = true
-gpui = { workspace = true, features = ["test-support"] }
+gpui.workspace = true
 http_client.workspace = true
 log.workspace = true
 paths.workspace = true