refactor(header): comment out unused CTA block for future use

Comment out the unused CTA block in the header component to 
preserve the layout for future implementation. This change 
ensures that the code remains clean while allowing for easy 
reinstatement once the necessary features for concepts and 
challenges are available.

Author: rohitpaulk

app/components/track-page/header/index.hbs

@@ -29,7 +29,9 @@
     {{#if (has-block "cta")}}
       {{yield to="cta"}}
     {{else}}
-      <div class="flex items-center flex-wrap gap-x-2 gap-y-4 mt-5">
+      {{!-- TODO: Bring this back once we can account for both concepts & challenges --}}
+
+      {{!-- <div class="flex items-center flex-wrap gap-x-2 gap-y-4 mt-5">
         {{#if this.currentUserHasStartedTrack}}
           <TrackPage::ResumeTrackButton @language={{@language}} @courses={{@courses}} />
         {{else}}
@@ -47,7 +49,7 @@
             <span class="text-xs text-gray-600 dark:text-gray-400 ml-2">Join the best</span>
           </div>
         {{/if}}
-      </div>
+      </div> --}}
     {{/if}}
   </div>
   <div class="ml-4 hidden md:flex h-36 w-36 flex-shrink-0">