Fix inconsistencies in email and phone normalization (#898)

[jradcliff]

Make email and phone number normalization consistent across all audience and conversion upload examples:

• Apply Gmail-specific normalization by removing periods (.) and plus (+) suffixes from gmail.com and googlemail.com usernames.
• Add E.164 phone number validation (^+[1-9]\d{6,14}$) and throw an IllegalArgumentException if phone numbers do not match this format.
• Update sample records across remarketing examples to conform to E.164 phone formatting and demonstrate Gmail domain normalization.