feat: add type conversion when submitting element values

[lcschy]

Description

• Adds the getValueType option for converting element value types before sending to API.

• ⚠️ BREAKING CHANGE:

  • The month and year methods of CardExpirationDateUITextField will now send Int values to the API.
  • This will cause any tokenization response w/ these values to also return Int.

Testing required outside of automated testing?

• Not Applicable

Screenshots (if appropriate):

• Not Applicable

Rollback / Rollforward Procedure

• Roll Forward
• Roll Back

Reviewer Checklist

• Description of Change
• Description of outside testing if applicable.
• Description of Roll Forward / Backward Procedure
• Documentation updated for Change