Use CAPITALIZATION_FOR_BEGINNING_OF_SENTENCE...

Use CAPITALIZATION_FOR_BEGINNING_OF_SENTENCE in place of
CAPITALIZATION_FOR_STANDALONE for date formats, since ICU does not
capitalize (at least) month names correctly today according to
https://unicode-org.atlassian.net/browse/ICU-21631. The motivating
example is the DatePicker/SimpleMonthView for Vietnam with "{month}
{year}" (as used in the manual date selection in the Date & Time screen
of the System settings): it does not capitalize the month without this
change.

It's difficult to know which formats will be affected, so this change
modifies all the formats found in frameworks/base/ that currently
express a preference for STANDALONE. The fix may be available by ICU 72,
at which point this change can presumably be reverted as signified in
the TODOs.

Bug: 229287642
Test: Inspection of Date & Time settings + compilation only
Change-Id: Iea753d0318aef55c6dd4f7e09068a0362ac970d8