* If `FunctionsSerializer` is given an object of unsupported type to encode, it throws an error
* However, if that object is contained in a dictionary, `FunctionsSerializer` crashes the app because of a force-unwrap
* The change fixes this inconsistency
* Additionally, array decoding no longer uses an `if-let` and instead inserts the optional value `as Any`
* Overall, this change achieves consistency in encoding and decoding of collections: Any non-codable element fails the operation, without crashing the app or resulting in missing elements
* New tests were added to check these scenarios