ui: Adds definition-table class to RTT values table (#8286)

We changed our default definition list layout in
https://github.com/hashicorp/consul/pull/8117.

We replaced the default with a definition-table class but missed one
place where the old default was previously used.

This adds the definition-table class in RTT where it used to use the
default.

ui-v2/app/templates/dc/nodes/show/rtt.hbs

@@ -1,26 +1,28 @@
 <div id="round-trip-time" class="tab-section">
   <div role="tabpanel">
-    <dl>
-        <dt>
-            Minimum
-        </dt>
-        <dd>
-            {{format-number tomography.min maximumFractionDigits=2}}ms
-        </dd>
-        <dt>
-            Median
-        </dt>
-        <dd>
-            {{format-number tomography.median maximumFractionDigits=2}}ms
-        </dd>
-        <dt>
-            Maximum
-        </dt>
-        <dd>
-            {{format-number tomography.max maximumFractionDigits=2}}ms
-        </dd>
-    </dl>
-<TomographyGraph @tomography={{tomography}} />
+    <div class="definition-table">
+      <dl>
+          <dt>
+              Minimum
+          </dt>
+          <dd>
+              {{format-number tomography.min maximumFractionDigits=2}}ms
+          </dd>
+          <dt>
+              Median
+          </dt>
+          <dd>
+              {{format-number tomography.median maximumFractionDigits=2}}ms
+          </dd>
+          <dt>
+              Maximum
+          </dt>
+          <dd>
+              {{format-number tomography.max maximumFractionDigits=2}}ms
+          </dd>
+      </dl>
+    </div>
+    <TomographyGraph @tomography={{tomography}} />
   </div>
 </div>