CommentPost content script tags not executed during oncreate

[clarkwinkelmann]

Bug Report

Current Behavior
When a post is loaded and its template contains javascript, the javascript doesn't run until the post experiences an onupdate cycle.

This can be experienced with syntax-highlighted code blocks, but probably also other extensions.

Steps to Reproduce

1. Create post with code block
2. Refresh page
3. See post is not highlighted

This can probably be reproduced with other community extensions. I think the code block is the only one from core with javascript in the template itself.

Expected Behavior
Javascript should run during the first render

Screenshots

Environment

• Flarum version: beta 14
• Website URL: tested locally

Possible Solution
We need to call the code from onupdate in oncreate. Previously that code ran in config without any regard to isInitialized.

Beta 13 code

https://github.com/flarum/core/blob/fd371c1203439810af8f6814cdff402faebf4126/js/src/forum/components/CommentPost.js#L57-L72

Current code

https://github.com/flarum/core/blob/c9a04fe009abf474b39f562e9d4bf13c5ecf25c8/js/src/forum/components/CommentPost.js#L59-L74

While we're at it, I think we should also call super.onupdate with a vnode parameter. If an extension was to extend Post.prototype.onupdate, they wouldn't be able to access vnode because CommentPost forgets to pass it up.

Additional Context
Reported by RebelCoderRU here https://discuss.flarum.org/d/25227-code-highlighting-not-working-properly-on-beta-14

[askvortsov1]

Unfortunately this doesn't fix the issue. From local testing, code blocks are highlighted during editing and not on a regular page because its shown in the ComposerPostPreview component. This chunk of code does nothing in beta 14 (which is probably the issue)