Add previous data on transform

[tkow]

Closes #7054

Add previous data argument transform method. My tests added is redundant because previousData always is passed and asserted in every tests but, it's noting worth to keep description about expecting behavior, ready for this behavior is modified (however if you don't need it, I'll remove them).

[djhi]

There are a lot of unrelated and unnecessary changes here due to your markdown formatter probably. Can you please revert them?

[tkow]

Sure. Maybe my editor or prettier convert trailing space, I'll fix it asap.

[djhi]

Suggested change

	**Tip**: `<Edit>`'s transform prop can recieve below variables from second argument.
	| field | Description |
	| -------------- | ------------------------------------------------------------------------------------------ |
	| `previousData` | Previous data fetched or last updated on `dataProvider.update` |
	**Tip**: `<Edit>`'s transform prop function also get the `previousData` in its second argument:

[djhi]

Suggested change

	**Tip**: `<SaveButton>`'s transform prop inside `<Edit>` can recieve below variables from second argument.
	| field | Description |
	| -------------- | ------------------------------------------------------------------------------------------ |
	| `previousData` | Previous data fetched or last updated on `dataProvider.update` |
	**Tip**: `<Edit>`'s transform prop function also get the `previousData` in its second argument:

[tkow]

@djhi
Now, I revised them, and please review again when you have time.

Vercel – react-admin-storybook's deploy is failed. Is that no problem?

[tkow]

@djhi I'm sorry, but I couldn't find why Vercel - react-admin-storybook deployment has failed because I have no idea to know that without vercel logs. It can be build in my local environment.
Could you help me when you have time?

[fzaninotto]

check the linter warning for missing dependency

[tkow]

Thank you I've not noticed. It's green now.

[fzaninotto]

I'd prefer that the transform function signature be (data, previousData)

[tkow]

@fzaninotto

Sorry, but I'd prefer my way, because it rarely breaks user code when we need to add more optionalData compared to push it to the tail of arguments though the change may be seldom.
Increasing arguments have risks when we want to add new argument, intermediate arguments can't change order without breaking change and even if they are not used in some cases, we may need to assign undefined like, (data, undefined, someEditControllerParameter) when we call or when we set no used variables' specification like, (data, _, someEditControllerParameter) as event hander.

Argument addition as option is better way for me if the argument is really optional value. In this case, users can ignore previousData so, it's optional value.
But, I can't say that previousData must be optional form because I haven't found the case we need more additional parameter in the future. My point is opposite to YAGNI, and previousData may be just enough parameter in all edit controller context parameters to satisfy user demands. So, I'll fix that if you still want to do nonetheless you have read this comment.

[fzaninotto]

The react-admin-storybook deployment randomly fails, don't worry about It. I redeployed it manually.

[fzaninotto]

we'll wait for #7087 to be merged to merge this one, as I prefer that you rebase your small PR rather than asking @djhi to rebase his mega-jumbo-huge-not-so-small PR.

[tkow]

I rebased my commits to remove no diff against next branch merged commits and fixing reviewed commits.

[fzaninotto]

Thanks!