ext6migrate: fix store load race condition

ext6migrate: fix store load race condition

when we click on a node/container/vm and quickly
click on something else, there might be a race condition,
where the store finished loading and we try to change
dom elements, which are not there anymore

so we change the store.on to me.mon, which
deletes the handler when the component is gone

in the logview panel we use API2Request, where
we cannot do this, so we check if the component
is destroyed manually

also we change this whenever we change a dom element
in a callback

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