Investigate possible memory leaking of NSDictionary when it is used in MSIDMacTokenCache

[antrix1989]

// Using the dictionary @{ key : value } syntax here causes _cache to leak. Yay legacy runtime!
NSDictionary *wrapper = [NSDictionary dictionaryWithObjectsAndKeys:cacheCopy, @"tokenCache",@CURRENT_WRAPPER_CACHE_VERSION, @"version", nil];