[CodeHealth] Remove outdated TODO in SmsService

crbug.com/1024598 was closed as wont fix because there is no intention
to add UMA for that purpose.

Bug: None
Change-Id: Id3da27a9035eda136a340341fbb1ecc720e5a132
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2334348Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798803}

content/browser/sms/sms_service.cc

@@ -119,10 +119,8 @@ void SmsService::Receive(ReceiveCallback callback) {
   // a new subscription is unnecessary. Note that it is only safe for us to use
   // the in flight otp with the new request since both requests belong to the
   // same origin.
-  if (consent_handler_->is_active()) {
-    // TODO(crbug.com/1024598): Add UMA histogram.
+  if (consent_handler_->is_active())
     return;
-  }
 
   fetcher_->Subscribe(origin_, this, render_frame_host());
 }