experiment: Separate retries from execution engine

[desertaxle]

This PR is an experiment to see if we can refactor the task/flow execution engines to extract a pure retry implementation out of them.

The result is a @retry decorator that can be used like so:

from prefect.retries import retry

attempts = 0

@retry(attempts=3)
def my_function(x: int) -> int:
    global attempts
    attempts += 1
    if attempts < 3:
        raise Exception("This is a test exception")
    else:
        return x + 1


my_function(1)

The retry lifecycle is instrumented with callbacks so that users of the retry functionality can take action when the wrapped function succeeds, fails, before a retry delay, etc. These callbacks are used in the task run engine to replicate the existing retry functionality.

[codspeed-hq]

CodSpeed Performance Report

Merging #18042 will not alter performance

_{Comparing retry-refactor (da5c5d3) with main (27cccbf)}

Summary

✅ 2 untouched benchmarks