SlackResponse.addReaction should throw Exception incase of permission issue

[Avi-Gupta1]

Jenkins and plugins versions report

Environment

It would be good to get Exception/Error for permission issue as well.
Wasn't able to find the issue, without re-reading the docs.

What Operating System are you using (both controller, and any agents involved in the problem)?

Jenkins is setup on ubuntu

Reproduction steps

1. Use slackResponse.addReaction with try and catch and remove (reaction) permission from the slack app.

Expected Results

Some Error/Exception which throws expection for permissions bit.

Actual Results

No, exception for missing permission

Anything else?

No response

Are you interested in contributing a fix?

Yes, I am interested.
would help if there is some devs specific doc.