[5.8] Fix View contract violations

[X-Coder264]

1. There was no method on the contract to access the view data even though one was obviously needed - this also meant that all the code in the framework which was trying to access the view data was violating the contract (e.g. in TestResponse). The ensureResponseHasView literally checks if $this->original is an instance of the View contract and then after that the data is accessed like this: $this->original->$key (this would obviously break with any other implementation of the contract). Fixing this requires adding the getData method to the contract.

2. The assertViewIs method in TestResponse was calling the getName method which is not on the contract, while name is and should be used instead as it gives the same result.