fix: show progress while loading deb search - #2192

Thanks for the fix, @skdas20! The approach of keeping autocomplete on the original provider and using a separate one for the results page looks good.

One concern: I ran shows progress when switching to deb search against the base versions of appstream_search.dart and search_page.dart, and it still passes. It finds a YaruCircularProgressIndicator even without the fix, so it wouldn't catch a regression. Could you tighten it so it fails on the old code? For example, assert that the "no results" text is absent while init() is pending and present after initialized.complete(), and scope the indicator lookup to the deb results.

Also, the CLA check is failing, so it will need to be signed before this can be merged.

Thanks again!

Thanks @ogres, good catch. The CLA is now signed. I'll tighten the test so it fails on the base version: assert the "no results" text is absent while init() is pending and present after initialized.complete(), and scope the progress-indicator lookup to the deb results.

Yes. appstreamSearchProvider is still used by search_provider.dart for autocomplete, where returning an empty list while AppStream initializes keeps typing responsive. The new appstreamSearchWithLoadingProvider is used only by the full Debian results page and its retry path, where waiting for initialization lets the UI show progress instead of a premature empty result. They share _search; the separate providers preserve those two behaviors.