fix: shorebird preview to identify shorebird projects with flavors

packages/shorebird_cli/lib/src/commands/preview_command.dart

@@ -88,10 +88,20 @@ class PreviewCommand extends ShorebirdCommand {
 
     final shorebirdYaml = shorebirdEnv.getShorebirdYaml();
     final String? appId;
+
+    final flavors = shorebirdYaml?.flavors;
+
     if (results.wasParsed('app-id')) {
       appId = results['app-id'] as String;
-    } else if (shorebirdYaml != null && shorebirdYaml.flavors == null) {
+    } else if (shorebirdYaml != null && flavors == null) {
       appId = shorebirdYaml.appId;
+    } else if (shorebirdYaml != null && flavors != null) {
+      final flavorOptions = flavors.keys.toList();
+      final choosenFlavor = logger.chooseOne<String>(
+        'Which app flavor?',
+        choices: flavorOptions,
+      );
+      appId = flavors[choosenFlavor];
     } else {
       appId = await promptForApp();
     }

packages/shorebird_cli/test/src/commands/preview_command_test.dart

@@ -712,31 +712,32 @@ channel: ${track.channel}
         verifyNever(() => codePushClientWrapper.getApps());
       });
 
-      test('prompts for app id when in shorebird project with flavors',
+      test('prompts for the flavor when in shorebird project with flavors',
           () async {
         when(() => shorebirdEnv.getShorebirdYaml()).thenReturn(
           const ShorebirdYaml(
             appId: 'test-app-id',
-            flavors: {'dev': 'dev-app-id'},
+            flavors: {
+              'dev': 'dev-app-id',
+              'prod': 'prod-app-id',
+            },
           ),
         );
         when(() => argResults.wasParsed('app-id')).thenReturn(false);
         when(() => argResults['app-id']).thenReturn(null);
         when(
-          () => logger.chooseOne<AppMetadata>(
+          () => logger.chooseOne<String>(
             any(),
             choices: any(named: 'choices'),
-            display: any(named: 'display'),
           ),
-        ).thenReturn(app);
+        ).thenReturn('dev');
 
         await runWithOverrides(command.run);
 
         verify(
-          () => logger.chooseOne<AppMetadata>(
-            'Which app would you like to preview?',
-            choices: any(named: 'choices'),
-            display: any(named: 'display'),
+          () => logger.chooseOne<String>(
+            any(),
+            choices: ['dev', 'prod'],
           ),
         ).called(1);
       });