feat: resolve Search loading gates from snapshot terminal state

[BartekObudzinski]

Explanation of Change

The Search page decides whether to show its loading skeleton from the shape of the snapshot data (data === undefined) and a stored search.isLoading flag. Both can lie: a successful response that writes no snapshot data leaves data undefined forever, and a reload or dropped response can strand isLoading, so the skeleton hangs indefinitely with no request running.

This change moves the Search loading gates onto the snapshot's explicit terminal lifecycle state (loading | loaded | error), which the search action always resolves on success, failure, or a network-level rejection:

• isSearchDataLoaded treats a terminal loaded/error state as resolved, so a response that carried no data hands off to Search's own empty view instead of pinning the skeleton. The existing type/hash match still rejects a stale snapshot that Onyx can transiently return for the previous query.
• useSearchLoadingState stops the page skeleton once the request resolves.
• The page-setup re-fire effect no longer gates on the stored isLoading flag. It relies on resolved snapshot data plus the search action's existing in-flight de-duplication, which resets on reload, so a stranded loading state re-fires and self-heals instead of blocking forever.
• The narrow-layout loading bar reads the pending state from the lifecycle instead of the stored flag.
• The success and failure snapshot writes now stamp the query hash (alongside type) so a terminal state satisfies the anti-stale match even on a response that carried none of its own metadata.
• A dataless success (jsonCode 200 with no snapshot data) now logs a diagnostic so this previously-invisible case stays queryable.

Adds a helper isSearchPending(searchResults) and unit tests for the terminal-state read side. Healthy paths are unchanged; the only behavior difference is that a resolved-but-dataless response now shows the empty view instead of an endless skeleton.

Fixed Issues

$
PROPOSAL:

Tests

1. Open the Search page (e.g. Reports, or a saved search). Verify the loading skeleton appears, then results render.
2. Run a search whose query returns no results. Verify the empty state renders instead of an endless skeleton.
3. Switch quickly between different search queries. Verify each query shows its own results and no stale results flash in.
4. Reload the app while a search is loading, then reopen the Search page. Verify the search re-fires and resolves (no stuck skeleton).

• Verify that no errors appear in the JS console

Offline tests

1. On the Search page, turn off the network. Verify the offline indicator shows and there is no infinite skeleton.
2. Turn the network back on. Verify the search re-fires and results render.

QA Steps

Same as tests.

• Verify that no errors appear in the JS console

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I followed proper code patterns (see Reviewing the code)
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• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I followed the guidelines as stated in the Review Guidelines
• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
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  • A similar style doesn't already exist
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• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari