(docs) Fixes Server Actions example

[shuding]

Closes #53910.

[schimi-dev]

I am not sure if the original issue was actually a bug in the code sample.

From how I understand this, the function named action is actually a Client Action that internally calls the Server Action named updateItem. Then, the form receives that Client Action (not the Server Action directly) as action prop.

Using Server Actions composed within Client Actions that way seems to work quite well from what I tested. Maybe it would be good to state in the docs whether it is an allowed pattern to wrap Server Action in Client Actions and then pass that Client Action as action prop to a form.

Technically, this patterns seems to work perfectly fine at the moment, and I think there might be a lot of use cases for it (e.g. Client-side Form validation or preprocessing of data, so that you do not have to pass FormData to the Server Action but some already preprocessed custom object).