Use h tag for widget title instead of b tag (#12504)

* Change b tag to h3 tag

* Remove margin

* Update snapshots

res/css/views/rooms/_AppsDrawer.pcss

@@ -216,6 +216,11 @@ limitations under the License.
             margin-right: 12px;
         }
 
+        h3 {
+            font-size: inherit;
+            margin: 0;
+        }
+
         > :last-child {
             margin-left: 9px;
             display: flex;