DPWA: use GetAppEffectiveDisplayMode for ukm recording

Fix UKM metrics recording to use GetAppEffectiveDisplayMode instead of
GetAppDisplayMode to record the actual mode when user is interacting with
the app.

Bug: none
Change-Id: Ia9d0fa5e62d3bc80ed2731ce6595bff919ed9e54
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2591869Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Commit-Queue: Phillis Tang <phillis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836921}

chrome/browser/ui/web_applications/web_app_metrics.cc

@@ -306,7 +306,7 @@ void WebAppMetrics::UpdateUkmData(WebContents* web_contents,
     features.install_source =
         GetLatestWebAppInstallSource(app_id, profile_->GetPrefs());
     DisplayMode display_mode =
-        provider->registrar().GetAppUserDisplayMode(app_id);
+        provider->registrar().GetAppEffectiveDisplayMode(app_id);
     features.effective_display_mode = static_cast<int>(display_mode);
     // AppBannerManager treats already-installed web-apps as non-promotable, so
     // include already-installed findings as promotable.