Adjust color of icon on “no annotations in group” messaging

- Also tighten padding as it was a little loose

src/styles/sidebar/components/selection-tabs.scss

@@ -15,6 +15,11 @@
   padding-bottom: 10px;
 }
 
+.selection-tabs__icon {
+  color: var.$grey-mid;
+  margin: 0 0.25em;
+}
+
 .selection-tabs--theme-clean {
   margin-left: 15px;
 }
@@ -58,6 +63,6 @@
 .selection-tabs__message {
   color: var.$color-text;
   border: 1px solid var.$grey-3;
-  padding: 3em;
+  padding: 2em;
   text-align: center;
 }