DataViews: improve out-of-bounds page empty state messaging and pagination.

[shail-mehta]

What?

Closes #80840

• Shows a specific empty state message for out-of-bounds pages: "No results on this page".
• Keeps pagination/page switcher visible so users can navigate back to valid pages.
• Handles rest_post_invalid_page_number in core-data by recovering pagination metadata from page 1 and returning an empty result set for the requested page.
• Adds/updates tests for both DataViews UI behavior and core-data resolver fallback.
• Adds changelog entries in Dataviews and core-data.

Why?

• In the issue scenario, users see generic "No results" with no clear indication that results exist on other pages.
• This is confusing when URL pageNumber is out of bounds.
• The fix aligns behavior with the issue expectation: clear out-of-bounds message + visible page switcher.

How?

• Detects out-of-bounds state when totalItems > 0, totalPages > 0, and view.page > totalPages.
• Uses out-of-bounds copy for default empty state.
• Ensures pagination select remains functional when current page is out-of-range.

Testing Instructions

• Clear any saved view before proceeding (View config → Reset view).
• Load theme test data.
• Ensure page dataset has “level” matches (about 8–9 records is fine).
• Open http://localhost:8888/wp-admin/site-editor.php?p=%2Fpage&pageNumber=5&search=level then
  Verify:
• Empty state shows "No results on this page".
• Pagination/page switcher is visible.
• You can navigate back to valid pages and see results.
• Open a true-empty search like: http://localhost:8888/wp-admin/site-editor.php?p=%2Fpage&search=fmjfajf Verify generic "No results" still appears.

Use of AI Tools

• Yes

[github-actions]

Size Change: +537 B (+0.01%)

Total Size: 7.76 MB

📦 View Changed

Filename	Size	Change
build/modules/content-types/index.min.js	166 kB	+107 B (+0.06%)
build/scripts/core-data/index.min.js	36.5 kB	+75 B (+0.21%)
build/scripts/edit-site/index.min.js	306 kB	+86 B (+0.03%)
build/scripts/editor/index.min.js	501 kB	+146 B (+0.03%)
build/scripts/media-utils/index.min.js	122 kB	+123 B (+0.1%)

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[github-actions]

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Co-authored-by: shail-mehta <shailu25@git.wordpress.org>
Co-authored-by: oandregal <oandregal@git.wordpress.org>

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