Better guide users when cross-entity transactions are needed but not enabled in configuration

[andreasohlund]

Describe the suggested improvement

Is your improvement related to a problem? Please describe.

The default transaction mode is SendsAtomicWithReceive and for that to work cross entity transactions needs to be enabled in host.json. This is easy to forget and a cryptic exception at runtime is not that helpful.

Describe the suggested solution

Find a way to detect this and make it clear to the users what they need to do. Can we perhaps enable this for them somehow?

Describe alternatives you've considered

Additional Context

No response