JobDetails: Show message when job has no settings or metadata

Avoid an empty tab by displaying a message if there's no data.

web/app/src/assets/base.css

@@ -1,5 +1,6 @@
 :root {
   --spacer: 1rem;
+  --spacer-lg: 1.33rem;
   --spacer-sm: .66rem;
   --spacer-xs: .33rem;
 
@@ -236,6 +237,15 @@ dl dd:empty {
   border-color: transparent;
 }
 
+.dl-no-data {
+  color: var(--color-text-hint);
+  font-family: var(--font-family-mono);
+  font-size: var(--font-size-sm);
+  padding: var(--spacer-lg) var(--spacer);
+  text-align: center;
+  cursor: default;
+}
+
 .window-footer {
   align-items: center;
   background-color: var(--color-background-column);

web/app/src/components/jobs/JobDetails.vue

@@ -12,6 +12,9 @@
             <dd>{{ value }}</dd>
           </template>
         </dl>
+        <div v-else class="dl-no-data">
+          <span>This job has no settings.</span>
+        </div>
       </TabItem>
       <TabItem title="Metadata">
         <dl v-if="hasMetadata">
@@ -20,6 +23,9 @@
             <dd>{{ value }}</dd>
           </template>
         </dl>
+        <div v-else class="dl-no-data">
+          <span>This job has no metadata.</span>
+        </div>
       </TabItem>
       <TabItem title="Details">
         <dl>