[web] migrate from window attributes to getMeta GitOrigin-RevId: 3dcf1ab6b01155e5e4abeb3e78d0fa9053e055bc
* Notify about unsaved changes * Move system message components and types to shared folder * Add system messages component GitOrigin-RevId: ab81a24888847bd9a8a390fd1af6b58f471f7a4b