WebHook JQL should be checked upon transition completion

Summary

At the moment, Issue Updated event is listened by a WebHook when:

1. An issue is updated (Issue Updated) either in Edit Issue screen (clicking the Edit button) or in View Issue screen (inline-update)
2. An issue is transitioned (Issue Transitioned)

If a WebHook is configured with a JQL, currently the JQL is checked when:

1. For Issue Updated, after the issue is updated
2. For Issue Transitioned, when the transition button is clicked, or before the post-functions are executed

This causes some confusion and/or unexpected behaviors, and some requirements can't be achieved.

Scenario / Steps to reproduce

1. Create a Select List custom field named Counter with 2 options: One and Two
2. Add the field to a Transition screen and all Create/Edit/View Issue screens of project ABC
3. Create a WebHook with this configuration:
   • JQL:

     project = ABC and Counter = Two

   • Events: Issue Updated only
4. Create an issue ABC-1 and ensure its Counter value is not Two

Scenario 1 - Issue Updated

1. Edit the field Counter either inline or in Edit Issue screen for ABC-1 -> Set its value to Two
   The WebHook is triggered as expected.
2. Edit the field Counter either inline or in Edit Issue screen for ABC-1 -> Set its value to One (or None)
   The WebHook is not triggered.

Scenario 2 - Issue Transitioned (the opposite behavior)

1. When Counter is not Two, transition ABC-1 and set Counter to Two on the transition screen -> Complete the transition
   The WebHook is not triggered as expected.
2. When Counter is Two, transition ABC-1 and set Counter to One (or None) on the transition screen -> Complete the transition
   The WebHook is triggered.

Notes

1. This behavior not only applies to a Select List custom field, but also to other fields if they're updated on a Transition screen. Known related issues are:
   • For Status: JRASERVER-65174 - Webhook is not triggered correctly when the JQL is describing a specific status.
   • For Status (different JQL): JRACLOUD-65293 - Transition doesn't trigger webhook if JQL contains 'updated after' with relative time
   • For Assignee: JRASERVER-62919 - Webhook based on JQL would not trigger when used in Workflow Post Functions
2. This behavior can't be worked around using WebHook Post-function. For example, if the WebHook is added to the post-function list of the Transition, it's not fired either (following Scenario 2), regardless of the order of the post-function.
   One may expect that, if the WebHook Post-function is after the Issue Re-index Post-function, the WebHook should be triggered.