node/Task: show errors on store load

node/Task: show errors on store load

since we use a buffered store on a grid, we cannot use our
normal monStoreErrors from Utils (The store on the grid is a memorystore
without our 'proxmox' proxy, and the store in the viewmodel is not
initialized yet in the init)

simply set the mask in the already existing 'updateLayout' function
which is exactly the right place for the buffered store load

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>