Allow users to enable non-root auth in simulation

[dmkozh]

What problem does your feature solve?

Currently simulation by default disallows 'non-root' authorization in recording mode, i.e. disallows potentially 'frontrunnable' authorizations. This is a very sensible default setting as most of the time it's correct to make all the calls non-frontrunnable. That said, there is still a range of cases where non-root auth is intentional and thus we need to provide users with a way of enabling this.

What would you like to see?

There should be some request parameter that enables non-root auth. It's fine for this to be not easily discoverable or accessible as this is meant for the advanced users. But there needs to be at least some way of enabling this.

What alternatives are there?

Not providing the users with an option. This basically makes auth simulation unusable for a fraction of the users, which is not desirable.

[dmkozh]

This requires an env release as well. I'll work on this and assign this to myself for the time being. It would be great if someone else could help with the RPC interface part when the env change is released.

[dmkozh]

The env-side change has been released in 22.1.3 release (stellar/rs-soroban-env#1503) and it can be now implemented in soroban-rpc at any time now.

It had to be guarded by unstable-next-api feature in order to pass the semver checks, which should be fine to enable in soroban-rpc as we'll be aware of the dependency and will make sure to not accidentally break it (should there be any more API-breaking features before v23 release).

The alternative is to wait until the stable v23 release, though it might be a good idea to at least prepare the change before that.