[TT-13712] Extend gw debug endpoint to support oas

[lghiur]

https://tyktech.atlassian.net/browse/TT-13712

Description

Context

At the moment our Dashboard and Gateway API for debugging, accept just classic api definitions. This is a problem for the onboarding flow since we want to be able to trigger requests for Tyk OAS API Definitions.

What will we do

• We are going to extend the POST /api/debug to accept Tyk OAS API Definitions.

• the API will be able to receive oas entry instead of spec

• if both oas and spec are present, then the oas one will take precendence

Related Issue

Motivation and Context

How This Has Been Tested

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Refactoring or add test (improvements in base code or adds test coverage to functionality)

Checklist

• I ensured that the documentation is up to date
• I explained why this PR updates go.mod in detail with reasoning why it's required
• I would like a code coverage CI quality gate exception and have explained why