Fix fileActionsReady event after deferred file actions update
Use fileActionsReady to re-render sharing icons

Whenever file actions are modified, either by registering new actions or
when appending a new page of entries, the sharing app is now notified so
it can correctly refresh the sharing icon status.

Additionally, the core's loadIcons() method is also used to load the
existing shares and also refresh the sharing icons afterwards.
Merge pull request #9341 from owncloud/sharing-fileactions-fix

Fix fileActionsReady event after deferred file actions update