Validates a raw phone string.
Accepts any number whose local body (after stripping the country-code prefix)
contains exactly 10 digits.
PhoneInput always sends strings in the form "+ ", e.g.
"+1 (780) 555-0100"
We split on the first space so the prefix digit(s) are NOT counted as part
of the 10-digit body. Returns e164 = prefix + 10bodyDigits.
Validates a raw phone string. Accepts any number whose local body (after stripping the country-code prefix) contains exactly 10 digits.
PhoneInput always sends strings in the form "+ ", e.g.
"+1 (780) 555-0100"
We split on the first space so the prefix digit(s) are NOT counted as part
of the 10-digit body. Returns e164 = prefix + 10bodyDigits.