Remove delete button in shared with others list

Whenever a file is shared with others or with link, a delete button used
to be visible that triggered a direct deletion.

This button has been removed to avoid accidental deletion from people
who might believe it was an unshare button. Unsharing is still possible
inside the share dropdown.
JSHint fixes in sharedfilelistSpec unit test file
Merge pull request #12305 from owncloud/sharelist-nodelete

Remove delete button in shared with others list