[Housekeeping] Remove barrier transitions from FlytePropeller

[hamersaw]

Describe the issue

Currently, FlytePropeller manages plugin execution by processing a sequence of transitions that are either ephemeral or barrier. The barrier types are meant to ensure that the associated transition is reported before moving to another plugin transition. However, these transitions are stored in an in-memory cache and are therefore lost between restarts. So, they are essentially a very good best effort. It is not clear that these are useful and only result in additional overhead and complexity.

What if we do not do this?

The current situations results in a minimal amount of unnecessary overhead for every execution, inflated memory costs in the barrier cache, and useless complexity in the codebase.

Related component(s)

No response

Are you sure this issue hasn't been raised already?

• Yes

Have you read the Code of Conduct?

• Yes