Add network ID parameter to wp_is_large_network()

[flixos90]

Since network options are globally accessible for every network (without involving any expensive switching function), we should add a $network_id parameter to wp_is_large_network() that will allow to check those conditions for a network other than the current one.

This enhancement is furthermore required in order to make #40384 and #40385 possible.

[flixos90]

40489.diff​ adds the $network_id parameter to the function as well as to the filter. Are there any objections to doing that in the way it happens in that patch, or in general?

We should definitely add thorough unit tests for both the function as well as different usages of the filter to verify things work as expected.

[flixos90]

40489.2.diff​ adds unit tests for the function and the filter:

• One test with data for the default function behavior.
• One test with data for a filter that only allows a maximum of 1000 when using 'users'.
• One test with data for a filter that only allows a maximum of 1000 for a specific network.

All test data includes variants with a different network than the current one, in order to test the actual changes from this ticket.

[flixos90]

In 40590:

Multisite: Add $network_id parameter to wp_is_large_network().

Now that get_blog_count() and get_user_count() both support passing a $network_id parameter (see [40370] and [40371]), similar functionality is now available for wp_is_large_network(). In addition, the filter wp_is_large_network now accepts the network ID as its fourth parameter.

This changeset furthermore introduces unit tests for the wp_is_large_network() function and its filter.

Fixes #40489.