Attach hx-on handlers before processing nodes

[rkilpadi]

Description

Currently, hx-on attributes are processed after triggers, causing issues where some triggers (i.e. load and sometimes revealed) are fired before hx-on handlers attach.
This change attaches hx-on attributes before triggers are processed. In doing so, the logic to conditionally de-init nodes had to be moved.
Discussion

Corresponding issue: #3106

Testing

• Added tests to ensure hx-on attributes are triggered on revealed and load

Checklist

• I have read the contribution guidelines
• I have targeted this PR against the correct branch (master for website changes, dev for
  source changes)
• This is either a bugfix, a documentation update, or a new feature that has been explicitly
  approved via an issue
• I ran the test suite locally (npm run test) and verified that it succeeded