Make ticket non-optional and add ensure_successful method to Consideration trait (#5359)

Make ticket non-optional and add ensure_successful method to
Consideration trait.

Reverts the optional return ticket type for the new function introduced
in
[polkadot-sdk/4596](https://github.com/paritytech/polkadot-sdk/pull/4596)
and adds a helper `ensure_successful` function for the runtime
benchmarks.
Since the existing FRAME pallet represents zero cost with a zero balance
rather than `None` in an option, maintaining the ticket type as a
non-optional balance is beneficial for backward compatibility and helps
avoid unnecessary migrations.