autotest api: delete outdated comments.

The code has been updated with self-evident variable names, so we can
delete the obsolete comments.

Bug: none.
Test: manually.
Change-Id: Ia73d990edb8d223b35a30ab621ca48e1ec7595c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1819682Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Commit-Queue: Meilin Wang <meilinw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#698996}

chrome/browser/chromeos/extensions/autotest_private/autotest_private_api.cc

@@ -1661,8 +1661,6 @@ AutotestPrivateSetAssistantEnabledFunction::Run() {
   if (!err_msg.empty())
     return RespondNow(Error(err_msg));
 
-  // |NOT_READY| means service not running;
-  // |STOPPED| means service running;
   auto new_state = params->enabled ? ash::mojom::AssistantState::READY
                                    : ash::mojom::AssistantState::NOT_READY;
   if (ash::AssistantState::Get()->assistant_state() == new_state)