Revert "Revert "goaidentity: Fix deadlock in goaalarm on_cancelled""

This reverts commit 53d660a4bb7841a2da5c7a94d23f96485105b926.
goaidentity: use proper main context

The previous commit uses the wrong main context, which ultimately
leads symptoms including crashes and 100% cpu usage.

This commit just tweaks the previous commit a little bit, to use
the proper context.
Assamese translation updated