Use different formatter for different currency (#1432)

* Use different formatter for different currency

* Add functional tests for currency fraction digit format

* Revert "Add functional tests for currency fraction digit format"

This reverts commit bd8aab33847425f4dcfd0d76ce310c918729b2fd.

* Add TestCurrencyFormattingLogic in UnitConverterViewModelUnitTests

* Fix InitializeMultipleConverterTest

* Add comment for a line of code

* Add default case for switch in ConvertToLocalizedString

* Remove trailing decimal
Disable decimal input if maxFractionDigits is 0
Fix input may be blocked after switched active

* Fix: UpdateIsDecimalEnabled should do nothing for non-currency converter

* Remove unnecessary SetValue method

* Add a comment

* Add functional UI Tests for currency converter
Reset currency before tests
Fix: input is blocked after switching to currency with less fractional digits

* Set Priority=0 for currency format related tests

* Truncate digits in display value after switcing
To fix incorrect result after switching currency with less fractional digits