Adding enterprise build hash to about dialog (#3058)

webapp/i18n/en.json

@@ -6,6 +6,7 @@
   "about.enterpriseEditionSt": "Modern enterprise communication from behind your firewall.",
   "about.enterpriseEditione1": "Enterprise Edition",
   "about.hash": "Build Hash:",
+  "about.hashee": "EE Build Hash:",
   "about.licensed": "Licensed by:",
   "about.number": "Build Number:",
   "about.teamEditionLearn": "Join the Mattermost community at ",