Remove kAppServiceAsh from Crostini test.

kAppServiceAsh is the flag to integrate AppService in UI app_list.
Since it has been enabled for a few months for M78, M79 release, it
should not be disabled, so the flag kAppServiceAsh can be removed.

BUG=1016159

Change-Id: I0235521beb53bdda1b50c07e8a6e4e11298ba71c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1895254Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Nancy Wang <nancylingwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712039}

chrome/browser/chromeos/crostini/crostini_test_helper.cc

@@ -108,7 +108,6 @@ void CrostiniTestHelper::ReInitializeAppServiceIntegration() {
     chromeos::DBusThreadManager::Initialize();
   }
 
-  if (base::FeatureList::IsEnabled(features::kAppServiceAsh)) {
   // The App Service is originally initialized when the Profile is created,
   // but this class' constructor takes the Profile* as an argument, which
   // means that the fake user (created during that constructor) is
@@ -123,7 +122,6 @@ void CrostiniTestHelper::ReInitializeAppServiceIntegration() {
   auto* proxy = apps::AppServiceProxyFactory::GetForProfile(profile_);
   proxy->ReInitializeCrostiniForTesting(profile_);
   proxy->FlushMojoCallsForTesting();
-  }
 }
 
 void CrostiniTestHelper::UpdateAppKeywords(