Fix missing zone strings in some cases

ICU's TimeZoneNames requires a "canonical" zone ID, otherwise it will
return no data. Usually the ID being used is the same as the canonical
ID so there's no problem. TZDB version 2020a switched the ID of one of
Greenland's zones from America/Godthab to America/Nuuk, and ICU/CLDR
hold their translation data against America/Godthab in the current
version of ICU on Android.

Bug: 155167041
Test: Manual - viewed settings on a device with the tzdb 2020a update
Change-Id: Ia89c777a832f8b41c8d56d3327a9b7370ba44b52