Fix RC Codable to handle arrays and dictionaries from plist defaults (#10046)

FirebaseRemoteConfigSwift/Sources/FirebaseRemoteConfigValueDecoderHelper.swift

@@ -40,9 +40,15 @@ struct FirebaseRemoteConfigValueDecoderHelper: FirebaseRemoteConfigValueDecoding
     return value.dataValue
   }
 
-  func jsonValue() -> [String: AnyHashable]? {
+  func arrayValue() -> [AnyHashable]? {
+    guard let value = value.jsonValue as? [AnyHashable] else {
+      return nil
+    }
+    return value
+  }
+
+  func dictionaryValue() -> [String: AnyHashable]? {
     guard let value = value.jsonValue as? [String: AnyHashable] else {
-      // nil is the historical behavior for failing to extract JSON.
       return nil
     }
     return value