IBinder/Binder is preserved by Upgrade Assistant

When Upgrade Assistant encounters an in-process model project with `IBinder` or `Binder`, it doesn't make any changes. This leads to two build errors after the upgrade. One is for the type itself in the function parameters:

>Error CS0246 The type or namespace name 'IBinder' could not be found (are you missing a using directive or an assembly reference?)

The other would be for any attributes that are defined in the function body which would interact with the `IBinder`. For example:

>Error CS0246 The type or namespace name 'BlobAttribute' could not be found (are you missing a using directive or an assembly reference?)

The latter should be maintained (it's an error within the function body). However, we should consider removing the `IBinder` parameter from the signature. This will just move the error to wherever the `IBinder` was used, but that will also be in the function body. A code comment should be added alongside this removal that explains the change and points them to https://aka.ms/af-dotnet-isolated-migration for instructions on how to change this behavior.