refactor(test-results-bar): simplify collapse button handling

Remove the onCollapseButtonClick arg from TopSection and move the collapse
button out of TopSection into the main component template. This consolidates
the collapse button logic and prepares for future UI refinements related to
log section resizing.

Author: rohitpaulk

app/components/course-page/test-results-bar/index.hbs

@@ -24,7 +24,6 @@
   >
     {{#if this.isExpanded}}
       <CoursePage::TestResultsBar::TopSection
-        @onCollapseButtonClick={{this.handleCollapseButtonClick}}
         @activeTabSlug={{this.activeTabSlug}}
         @onActiveTabSlugChange={{fn (mut this.activeTabSlug)}}
         @availableTabSlugs={{this.availableTabSlugs}}
@@ -47,9 +46,12 @@
         />
       {{/if}}
 
-      <div class="absolute top-[3px] left-0 right-0 flex items-center justify-center">
-        {{! TODO: Add this back when we have a way to resize the logs section. }}
-        {{! <div class="w-20 h-1 rounded-full bg-gray-700 cursor-ns-resize hover:bg-gray-600"></div> }}
+      <div
+        class="absolute top-0 right-0 flex px-6 py-5 items-center justify-center text-gray-500 hover:text-gray-400"
+        {{on "click" this.handleCollapseButtonClick}}
+        role="button"
+      >
+        {{svg-jar "x" class="w-5 h-5 fill-current"}}
       </div>
     {{/if}}
   </div>

app/components/course-page/test-results-bar/top-section.hbs

@@ -10,7 +10,4 @@
       />
     {{/each}}
   </ul>
-  <div class="flex items-center justify-center text-gray-500 hover:text-gray-400" {{on "click" @onCollapseButtonClick}} role="button">
-    {{svg-jar "x" class="w-5 h-5 fill-current"}}
-  </div>
 </div>

app/components/course-page/test-results-bar/top-section.ts

@@ -7,7 +7,6 @@ interface Signature {
   Args: {
     activeTabSlug: string;
     availableTabSlugs: string[];
-    onCollapseButtonClick: () => void;
     onActiveTabSlugChange: (slug: string) => void;
   };
 }