fix(graphcache): Record dependencies for __typename accesses

[kitten]

Summary

This changes the expected behaviour for when dependencies are recorded for caches accesses.

Note: Dependencies are basically entity or field keys marking a cache read or write. When a cache write updates a dependency, then all cache reads (i.e. queries) that have the same cache dependency will be updated accordingly, i.e. re-queried. This is how Graphcache issues updates to queries after cache writes.

While this wasn't a bug, any usage of cache.resolve(entity, '__typename') wouldn't actually record a dependency, which could cause confusion. The exception has now been removed.

Set of changes

• Remove dependency exception for accessing __typename on entities