assistant edit tool: Fix editing files in context (#26751)

When the user attached context in the thread, the editor model request
would fail because its tool use wouldn't be removed properly leading to
an API error.

Also, after an edit, we'd keep the old file snapshot in the context.
This would make the model think that the edits didn't apply and make it
go in a loop.

Release Notes:

- N/A

crates/assistant_tool/Cargo.toml

@@ -15,8 +15,9 @@ path = "src/assistant_tool.rs"
 anyhow.workspace = true
 collections.workspace = true
 derive_more.workspace = true
-language_model.workspace = true
 gpui.workspace = true
+language.workspace = true
+language_model.workspace = true
 parking_lot.workspace = true
 project.workspace = true
 serde.workspace = true