feat(wiremock): add partial body matching for POST/PUT/PATCH requests…

[Haisia]

Implementation Notes

Approach difference from the original issue:

Instead of using containing() with string manipulation (as suggested in #776),
this implementation uses matchingJsonPath + equalToJson for better reliability.

Why?

• JSON-aware matching (structure, not strings)
• Handles nested objects and formatting variations
• Resilient to whitespace and key ordering
• String matching breaks with complex values

Implementation:

requestContaining.forEach { (key, value) ->
  builder.withRequestBody(
    matchingJsonPath("$.$key", equalToJson(String(serde.serialize(value))))
  )
}