[DataUsage] UX enhancement

Some of the field didn't take eu languages into consideration.
Enhance it through changing the:
1. Format of display
2. Parser after user input
3. IME support for comma in eu language

Bug: 141536928
Test: Manual input and check for results
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=BillingCycleSettingsTest
Change-Id: Ia7afc88c9043e924f205f966c4091248261b0aee