Pass process json dicts in ci.yaml. (#2293)

This is to make the behavior consistent for json lists and dictionaries.

Bug: https://github.com/flutter/flutter/issues/114656
diff --git a/app_dart/lib/src/model/ci_yaml/target.dart b/app_dart/lib/src/model/ci_yaml/target.dart
index 0306e82..69bc9f2 100644
--- a/app_dart/lib/src/model/ci_yaml/target.dart
+++ b/app_dart/lib/src/model/ci_yaml/target.dart
@@ -220,7 +220,7 @@
       return true;
     } else if (value == 'false') {
       return false;
-    } else if (value.startsWith('[')) {
+    } else if (value.startsWith('[') || value.startsWith('{')) {
       return jsonDecode(value) as Object;
     } else if (newLineIssues.contains(key)) {
       return value.replaceAll('\\n', '\n');