Add Locale#script to Configuration proto.

Read/Write Locale#script along with language, country, and variant
for the Configuration proto.

Bug: 131507134
Test: atest UsageStatsDatabaseTest
Test: atest LocaleListTest [unit-test, cts, gts]
Change-Id: I09b7d3b2e6c6d339cbb75bf19f89251b777bbbe6