fix(hosts): expose controls for overflowing editor tabs (#1537)

* fix(hosts): expose controls for overflowing editor tabs

* test(hosts): mock resize observation in admin panel tests

src/ui/locales/en.json

@@ -116,6 +116,8 @@
     "updateLinkLabel": "Update available. Open the release notes on GitHub"
   },
   "common": {
+    "scrollTabsLeft": "Scroll tabs left",
+    "scrollTabsRight": "Scroll tabs right",
     "close": "Close",
     "minimize": "Minimize",
     "online": "Online",