This pull request adds 3 functions (and corresponding tests):
`testhelpers/response_validation.go`:
- `ValidateResponse`
- `ValidateResponseData`
field_data.go:
- `ValidateStrict` (has the "strict" validation logic)
The functions are primarily meant to be used in tests to ensure that the responses are consistent with the defined response schema. An example of how the functions can be used in tests can be found in #18636.
### Background
This PR is part of the ongoing work to add structured responses in Vault OpenAPI (VLT-234)
* go-secure-stdlib/parseutil to v0.1.4
* add TypeCommaStringSlice for json.Number
* add changelog entry
* upgrade go-secure-stdlib/parseutil to v0.1.4 in sdk
* move json number TypeCommaStringSlice test
* go mod download for api; go mod tidy
* Refactor table driven tests to use subtests
* sdk/framework: add TypeSignedDurationSecond FieldType
Adds the TypeSignedDurationSecond FieldType which accepts positive and
negative durations. The existing TypeDurationSecond FieldType does not
accept negative durations.
* Add tests for 0 for TypeDurationSecond and TypeSignedDurationSecond
