fix(editor): commit temporary actions to history only after resolving them

[hejtful]

Resolves #4241

Note: First commit is only cleaning up, second commit fixes the bug.

This took way longer to figure out than I'd like to admit 😬
The editor emits onChange events when actions are committed to history, not when actions are resolved.
For most changes, this doesn't matter, as we first resolve actions, then commit them to history.
There are, however, these "temporary" actions, used in asyncScalar. One use-case of asyncScalar is uploading an image, where we had the bug. And in these "temporary" actions, we were first committing actions to history, then resolving them, which led the editor to emit onChange before its state was updated.

I snooped around the code to see if I could find any reason for this difference between regular and "temporary" actions, and I couldn't find any. I also tested the editor, and everything seems to work fine, but it would be great if you could test a bit as well.

Explanation for "temporary" actions (asyncScalar): I believe these were initially created to support loading states of async actions. So once a user uploads an image, a temporary action would show a loading screen, and then a normal action would show the uploaded image and the temporary action would be removed from history. That would make sure that undo/redo works as expected -- never showing the loading screen. I couldn't figure out how to use this, though. Either the feature was never finished, or we broke it unknowingly.

@elbotho This also fixes the ___editor_preview -- the right side will now show the image as soon as it's uploaded.

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Name	Status	Preview	Updated (UTC)
frontend	✅ Ready (Inspect)	Visit Preview	Nov 6, 2024 2:02pm

[github-actions]

📦 Next.js Bundle Analysis for @serlo/frontend

This analysis was generated by the Next.js Bundle Analysis action. 🤖

⚠️ Global Bundle Size Increased

Page	Size (compressed)
global	104.42 KB (🟡 +1 B)

Details

The global bundle is the javascript bundle that loads alongside every page. It is in its own category because its impact is much higher - an increase to its size means that every page on your website loads slower, and a decrease means every page loads faster.

Any third party scripts you have added directly to your app using the <script> tag are not accounted for in this analysis

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Seven Pages Changed Size

The following pages changed size from the code in this PR compared to its base branch:

Page	Size (compressed)	First Load
/___editor_preview	530.25 KB (-5 B)	634.67 KB
/entity/create/[type]/[taxonomyId]	550.34 KB (-5 B)	654.75 KB
/entity/repository/add-revision/[...id]	550.07 KB (-5 B)	654.49 KB
/page/create	550.06 KB (-5 B)	654.48 KB
/taxonomy/term/create/[parent_id]/[id]	549.81 KB (-5 B)	654.23 KB
/taxonomy/term/update/[id]	549.76 KB (-5 B)	654.17 KB
/user/settings	551.75 KB (-5 B)	656.17 KB

Details

Only the gzipped size is provided here based on an expert tip.

First Load is the size of the global bundle plus the bundle for the individual page. If a user were to show up to your website and land on a given page, the first load size represents the amount of javascript that user would need to download. If next/link is used, subsequent page loads would only need to download that page's bundle (the number in the "Size" column), since the global bundle has already been downloaded.

Any third party scripts you have added directly to your app using the <script> tag are not accounted for in this analysis

Next to the size is how much the size has increased or decreased compared with the base branch of this PR. If this percentage has increased by 20% or more, there will be a red status indicator applied, indicating that special attention should be given to this.

[elbotho]

👍 thank you for the deep dive!
Not sure I would have figured that one out.

[LarsTheGlidingSquirrel]

I don't know enough about the relevant code but I tested the editor and performed a lot of undo/redo and found no issue.
Thank you for looking into this and finding a solution!