Log warning instead of error in Google contacts sync.
Log warning instead of error in Google contacts sync.

If there's a RequestError, it pretty much means that the developer hasn't
enabled the Google Contacts API. This shouldn't feed into error metrics.

Fixes T490.

gale320/sync-engine,closeio/nylas,ErinCall/sync-engine,PriviPK/privipk-sync-engine,PriviPK/privipk-sync-engine,gale320/sync-engine,ErinCall/sync-engine,Eagles2F/sync-engine,ErinCall/sync-engine,EthanBlackburn/sync-engine,jobscore/sync-engine,wakermahmud/sync-engine,jobscore/sync-engine,PriviPK/privipk-sync-engine,Eagles2F/sync-engine,closeio/nylas,wakermahmud/sync-engine,EthanBlackburn/sync-engine,nylas/sync-engine,Eagles2F/sync-engine,wakermahmud/sync-engine,nylas/sync-engine,gale320/sync-engine,gale320/sync-engine,EthanBlackburn/sync-engine,gale320/sync-engine,ErinCall/sync-engine,closeio/nylas,nylas/sync-engine,EthanBlackburn/sync-engine,wakermahmud/sync-engine,EthanBlackburn/sync-engine,Eagles2F/sync-engine,ErinCall/sync-engine,nylas/sync-engine,jobscore/sync-engine,PriviPK/privipk-sync-engine,wakermahmud/sync-engine,jobscore/sync-engine,Eagles2F/sync-engine,PriviPK/privipk-sync-engine,closeio/nylas