Explore flow environment support for triggerable flows

Context

From MR !210894 (merged) discussion: Since flows are currently triggerable only, they should be ambient only. However, Flow Registry v1 fully supports all environments (ambient, chat, etc.).

Questions to Explore

1. What happens if we define a flow that is chat and trigger it? Does the flow work?
2. Do we support all environments currently in how we treat flows?
3. Should our code be blocking the ability to define a trigger for a chat flow?
4. Should we currently not support chat flows if they shouldn't run in remote CI?

Considerations

These might be reasons why we should be opinionated about the environment people set in flow definitions, even when Flow Registry v1 supports them.

Related to MR: !210894 (merged)