UX: Show installed version with SHA instead of number of commits

Removes the "+ 437" string at the end of "v2.4.0.beta2 + 437",
and adds a link to the exact commit on github underneath.

app/assets/javascripts/admin/templates/version-checks.hbs

@@ -5,7 +5,10 @@
 
       <div class="version-number">
         <h4>{{i18n 'admin.dashboard.installed_version'}}</h4>
-        <h3><a href={{versionCheck.gitLink}} target="_blank">{{dash-if-empty versionCheck.installed_describe}}</a></h3>
+        <h3>{{dash-if-empty versionCheck.installed_version}}</h3>
+        <div class="sha-link">
+          (<a href={{versionCheck.gitLink}} target="_blank">{{versionCheck.shortSha}}</a>)
+        </div>
       </div>
 
       {{#if versionCheck.noCheckPerformed}}

app/assets/stylesheets/common/admin/dashboard.scss

@@ -626,10 +626,13 @@
       flex: 1 0 auto;
       white-space: nowrap;
     }
-    h4 {
+    h4, .sha-link {
       font-size: $font-down-2;
       margin-bottom: 0;
     }
+    .sha-link {
+      font-weight: normal;
+    }
   }
   .version-status {
     display: flex;