Meta API - get_cancellation_reasons

## Description

In version 1.1.0 of beckn, a new set of APIs has been introduced that can be used by the BAPs to fetch the meta information. One of the API is get_cancellation_reasons. In this BAP fetches the list of cancellation reasons from BPP. In Strapi plugin we need to implement the get_cancellation_reasons.

1. Create a suitable datamodel in Strapi , check if any existing data model can be used to provide the detail.
2. Create an endpoint in webhook to handle the request.
3. Implement the query logic to fetch the requested detail.
4. Test the endpoint from Strapi and the generic client layer.
5. Write unit test cases for the endpoint.

## Goals

- [ ] Implement fetch cancellation reason API in Strapi

## Expected Outcome

Strapi should be able to serve the get_cancellation_reasons API call from BAP.

## Acceptance Criteria

- [ ] Correct result is provided to BAP when a request for cancellation results is made to Strapi BPP.

## Implementation Details

It should be part of the strapi pugin and must follow the specification details here - https://github.com/beckn/protocol-specifications/blob/master/api/meta/build/meta.yaml

### Tech Skills Needed:

Strapi plugin development
Node Js

### Complexity

Medium

### Category

Enhancement

### Sub Category

Strapi plugin enhancement

Start with the Beckn meta.yaml specification and inspect the existing Strapi data models and webhook handlers for related meta APIs. Implement the cancellation-reasons flow, then verify it through Strapi and the generic client layer and add endpoint unit tests. Done means Strapi returns the correct cancellation reasons to the BAP.

Written by the indexing model from the issue text.