Verify v2 Validation Updates

[superchilled]

This PR adds some validtion checks to the Verify v2 implementation. Specifically it:

• Adds a check to the SMS class from setter to ensure that:
  • Numeric values are between 11 and 15 characters in length
  • Alphanumeric values are between 3 and 11 characters in length
• Adds a check to the WhatsApp class from setter to ensure that values are between 11 and 15 characters in length
• Adds a check in the Verify2#start_verification method to ensure that the brand argument is between 1 and 16 characters in length

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.31%. Comparing base (35e4214) to head (17cb17b).

:exclamation: Current head 17cb17b differs from pull request most recent head 22f9655. Consider uploading reports for the commit 22f9655 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #309 +/- ## ========================================== + Coverage 98.19% 98.31% +0.11% ========================================== Files 132 132 Lines 2333 2313 -20 ========================================== - Hits 2291 2274 -17 + Misses 42 39 -3 ```

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