Chore.throw error in mock

[RubenGeo]

AB#32398

Describe your changes

First merge in #6335

• We had an error on main where tried to post this transfer amount to intersolve 1626.0000000000002
  • This was caused by a floating point error
  • To fix this I added a math.round() to ensure that we always post an integer
• I want to prevent that we reintroduce this error again in the future
• So I added to our mock service that it throws an error if you call it using a non-integer
  • Since floating point errors do not appear in a consistent way it's not straight forward to create an automated test for this
  • But I think if we re-introduce this error again it will appear in our k6 tests this way
• I also do not want to spend too much time on this..
• What do you think @Reviewer

Checklist before requesting a review

• I have performed a self-review of my code
• I have added tests wherever relevant
• I have made sure that all automated checks pass before requesting a review
• I do not need any deviation from our PR guidelines

[Copilot]

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

services/121-service/src/payments/fsp-integration/intersolve-visa/intersolve-visa.api.service.ts:450

• Ensure that the rounding behavior is covered by tests.

const amountInCent = Math.round(amountInMajorUnit * 100);