removeCountryCodeFromMask results in incorrect phone mask for national numbers

[woelmer]

Calling this text formatter:

LibPhonenumberTextFormatter( country: usCountry, PhoneNumberFormat.national)

Will result in the following mask "0) 000-0000" It should be "(000) 000-0000"

There are a couple problems:

1. input_formatter.dart line 28: removeCountryCodeFromMask gets set to true even though the phone number is a national number and the inputContainsCountryCode is false.

2. Once removeCountryCodeFromMask is true country_data.dart line 188 will remove three characters from the beginning of the national mask therefore chopping off the area code portion of the national phone number mask.