refactor: use neverthrow in /:transactionId/otp/verify (part 6)

[mantariksh]

Builds on #1454

Problem

See #1450

Solution

This is the 6th part of the solution, which focuses on the POST /transaction/:transactionId/otp/verify endpoint. It includes the following additional improvements:

• Deletes the old verification.(controller|service).spec.ts and replaces them with verification.(controller|service).new.spec.ts
• Adds factory tests
• Logs form ID in all verification service functions

For reviewers

Note that in verification.service.spec.ts and verification.controller.spec.ts, the only new tests added were for verifyOtp and handleVerifyOtp respectively. The rest of the changes are due to the file renaming.

Tests

See #1450

[mantariksh]

TODO from previous PRs

• Use ErrorDto type
• Use transformMongoError
• Set default mock value in beforeAll instead of using mockReset
• Use date-fns
• Log form ID as well as transaction/field ID

[karrui]

lgtm