MM-23935 extend session expiry on user activity (#14275)

* MM-23935  extend session expiry on user activity

- if user types anything before a session expires the session will be extended to now + session length

- ensures new session expiries are not written to DB too frequently

- new session store func for updating session ExpiresAt

- session length defaults for mobile and web/ldap changed from 180 days to 30 days

api4/channel.go

@@ -1241,6 +1241,7 @@ func viewChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 
 	c.App.UpdateLastActivityAtIfNeeded(*c.App.Session())
+	c.ExtendSessionExpiryIfNeeded(w, r)
 
 	// Returning {"status": "OK", ...} for backwards compatibility
 	resp := &model.ChannelViewResponse{

api4/post.go

@@ -90,6 +90,7 @@ func createPost(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 
 	c.App.UpdateLastActivityAtIfNeeded(*c.App.Session())
+	c.ExtendSessionExpiryIfNeeded(w, r)
 
 	w.WriteHeader(http.StatusCreated)