Fixes Dictionary.GetKeys as well.
Fixes Dictionary.GetKeys as well.

Getting the keys is not straightforwardly fetching the keys, we need
to go into the list of raw keys, then from the entries object, fetch
the actual key value.

Added exception if/when a single dictionary entry has zero or more
than one value, both for GetKeys() and GetValues().

Related github issue: bridgedotnet/Bridge:3408.

AndreyZM/Bridge,bridgedotnet/Bridge,bridgedotnet/Bridge,bridgedotnet/Bridge,bridgedotnet/Bridge,AndreyZM/Bridge,AndreyZM/Bridge,AndreyZM/Bridge