Nav block Page List fallback displays too many Pages

[getdave]

By default the Nav block falls back to a Page List. However on a site with a lot of pages this is overwhelming.

The Page List does have an __unstableMaxPages attribute but this doesn't appear to be respected by Page List even though the Nav block index.php creates the block with this attribute.

This is strange as it was added in #36877.

We should make the Page List respect the limit.

[getdave]

Noting that the Nav block currently specifies 4 as the fallback

gutenberg/packages/block-library/src/navigation/index.php

Line 311 in 4287476

'__unstableMaxPages' => 4,

[draganescu]

The problem here is that the '__unstableMaxPages' is used only when rendering the block, but not in the editor.

[carolinan]

Aside, I have had users asking why this is limited to four in support requests, asking for this number to be increased.
So I think it can be confusing if not all pages show.

[getdave]

I've had a think about this overnight. I'm asking myself how many users will actually have this many top level pages? Answer is very few.

Let's optimise for the 80% use case here and avoid limiting the number of items shown. I'll raise a PR to remove the attribute from the Page List and another to remove the functionality from the Nav block.

Does that sound like a good course of action?