feat: implement metrics for AsyncFuncExec

[feniljain]

Which issue does this PR close?

• Closes Implement metrics for AsyncFuncExec #19623

Rationale for this change

Explained in issue

What changes are included in this PR?

Implement baseline metrics for AsyncFuncExec operator

Are these changes tested?

Have added a test with PR

Are there any user-facing changes?

There are user facing changes, now explain analyze will show metrics of AsyncFuncExec too, do we need to update any documentation regarding this? Asking cause I couldn't find anything on a quick search.

[2010YOUY01]

There are user facing changes, now explain analyze will show metrics of AsyncFuncExec too, do we need to update any documentation regarding this? Asking cause I couldn't find anything on a quick search.

Here is the doc for metrics https://datafusion.apache.org/user-guide/metrics.html
But we don't have to update it, since BaselineMetrics is already documented.

[feniljain]

Yup, had the same thought for BaselineMetrics documentation, thanks for the clarification! 🙇🏻

[2010YOUY01]

LGTM, thank you!