Refactor invoke_main_context_sync() and user for archive extraction password dialog
!657 (merged) implements invoking the main context for the dialog from an operation thread.
This duplicates existing code that caters the same use case for the file conflict dialog (invoke_main_context_sync()
from src/nautilus-operations-ui-manager.c).
Let's move the code handling the password dialog into the src/nautilus-operations-ui-manager.c file to make use of invoke_main_context_sync()
.