Add transform function to drop date of time fields

[luandy64]

Description of change

This PR transforms Google Sheet Time fields from "44241 days, 12:34:56" to "12:34:56"

Manual QA steps

• Ran the tap with target-stitch's `Validating Handler

Risks

• Low, the current tap errors because "44241 days, 12:34:56" is not a valid time format. So no downstream system should ever see a value like this.

Rollback steps

• revert this branch, bump the version