Do not update :mailserver/connection-checks` if the user is logged out.

Connection check should be skipped if the user has logged out, otherwise
`app-db` may end up in an invalid state which causes an error and red screen
in dev mode.

src/status_im/mailserver/core.cljs

@@ -364,12 +364,14 @@
    else
       change mailserver if mailserver is connected"
   [{:keys [db] :as cofx}]
-  (if (zero? (dec (:mailserver/connection-checks db)))
-    (fx/merge cofx
-              {:db (dissoc db :mailserver/connection-checks)}
-              (when (= :connecting (:mailserver/state db))
-                (change-mailserver cofx)))
-    {:db (update db :mailserver/connection-checks dec)}))
+  ;; check if logged into account
+  (when (contains? db :account/account)
+    (if (zero? (dec (:mailserver/connection-checks db)))
+      (fx/merge cofx
+                {:db (dissoc db :mailserver/connection-checks)}
+                (when (= :connecting (:mailserver/state db))
+                  (change-mailserver cofx)))
+      {:db (update db :mailserver/connection-checks dec)})))
 
 (fx/defn reset-request-to
   [{:keys [db]}]