Milo: Print raw json for buildbot build properties

milo/appengine/frontend/templates/buildbot/pages/build.html

 {{define "title"}}
   {{ with .Build.Summary -}}
     {{ if eq .Status.String "InfraFailure" }}
       Exception
     {{ else if eq .Status.String "Failure" }}
       Failed
     {{ else if eq .Status.String "NotRun" }}
       Pending
     {{ else }}
       {{ .Status.String }}
@@ skipping 175 matching lines @@
             <tr>
               <td class="left">{{.Key}}</td>
               <td>
                 {{ if (eq .Key "requestedAt") }}
                   {{ .Value | parseRFC3339 | localTime "" }}
                 {{ else if (eq .Key "blamelist") }}
                   {{ .Value | obfuscateEmail }}
                 {{ else if (startswith .Value "https://") }}
                   <a href="{{.Value}}">{{.Value}}</a>
                 {{ else }}
-                  {{.Value}}
+                  {{ .Value | formatJson }}
                 {{ end }}
               </td>
               <td>{{$name}}</td>
             </tr>
           {{ end }}
         {{ end }}
       </table>
 
       {{ if .Build.Blame }}
         <h2>Blamelist:</h2>
@@ skipping 58 matching lines @@
     }
   };
 
   check($("#showHidden").is(":checked"));
   $("#showHidden").click(function(e) {
     check($(this).is(":checked"));
   });
 });
 </script>
 {{end}}