Revert having edit_file_tool format on save (#31403)

An unintended consequence of format on save is that we start (correctly)
informing the model that the file changed on disk every time the
formatter changes anything, which in turn can lead the model to things
like extra reads.

Until we have a solution in place to prevent this downside, we're going
back to not formatting on save by reverting
cb112a4012.

Release Notes:

- N/A

Cargo.lock

@@ -682,7 +682,6 @@ dependencies = [
  "language_model",
  "language_models",
  "log",
- "lsp",
  "markdown",
  "open",
  "paths",