Use the REST pagination signal for tag lists

[jkmassel]

Suggestion for #25767 (base: bugfix/selfhosted-taxonomy-rest) — fixes a tag-list pagination bug.

Summary

• TagsViewModel inferred hasMore from remoteTags.count == 100, so a tag list whose size is an exact multiple of the page size (100, 200, …) requested a page past the last one.
• Once Fixes fetching terms on XML-RPC disabled sites #25767 routes built-in tags through AnyTermService (wp/v2, page-number paging), that over-page request returns 400 rest_term_invalid_page_number, surfacing a stuck pagination error footer. The prior offset-based path returned an empty page and stopped cleanly.

Root Cause

AnyTermService.getTags discarded the response's nextPageParams — wp/v2's authoritative "is there another page" signal — and returned only response.data, forcing TagsViewModel to guess hasMore from the item count. That guess is wrong exactly when the last page is full.

Fix

TaxonomyServiceProtocol.getTags now returns (terms:hasMore:):

• AnyTermService derives hasMore from response.nextPageParams != nil (the wp/v2 signal).
• TagsService keeps the count == pageSize check, which is safe for its offset-based XML-RPC / WP.com remotes — an over-offset request returns an empty page, not a 400.
• TagsViewModel uses the returned hasMore instead of count == 100.

Contained to the two getTags implementations and their single caller; no other conformers.

Test Plan

• Self-hosted (application password) or WP.com site with exactly 100 tags: open the tag picker, scroll to the bottom — no error footer, pagination stops cleanly.
• Site with a non-multiple-of-100 tag count (e.g. 150): all tags still load across pages.
• Custom taxonomy term lists still page correctly.
• Legacy self-hosted (XML-RPC, no application password) tag list still loads.

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📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	33239
	Version	PR #25804
	Bundle ID	com.jetpack.alpha
	Commit	f25653d
	Installation URL	1daa6jonabf38

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[crazytonyli]

that over-page request returns 400 rest_term_invalid_page_number

This error code does not seem to exist.

Here are curl test results:

$ curl -s --include -u "demo:${APP_PASSWORD}" 'https://frog-of-gamefowls.jurassic.ninja/wp-json/wp/v2/tags?context=view&per_page=100&page=2'
HTTP/2 200
x-wp-total: 100
x-wp-totalpages: 1

[]%

$ curl -s --include -u "demo:${APP_PASSWORD}" 'https://frog-of-gamefowls.jurassic.ninja/wp-json/wp/v2/tags?context=view&per_page=100&page=3'
HTTP/2 200
x-wp-total: 100
x-wp-totalpages: 1

[]%

I also can't reproduce the issue in the app.