feat(router): added support for optional defend dispute api call and added evidence submission flow for checkout connector

[sai-harsha-vardhan]

Type of Change

• [ ] Bugfix
• [x] New feature
• [ ] Enhancement
• [ ] Refactoring
• [ ] Dependency updates
• [ ] Documentation
• [ ] CI/CD

Description

1. added support for optional defend dispute api call in evidence submission flow if connector requires it.
2. added file upload and evidence submission flow for checkout connector.

Additional Changes

• [x] This PR modifies the API contract
• [ ] This PR modifies the database schema
• [ ] This PR modifies application configuration/environment variables

Motivation and Context

There is a use case where we have to do 2 api calls for evidence submission (for connectors like checkout, adyen)

1. Attach the evidence to dispute
2. Defend the dispute Added support for optional second call to connector to defend the dispute

How did you test it?

Tested Manually

Checklist

• [x] I formatted the code cargo +nightly fmt --all
• [x] I addressed lints thrown by cargo clippy
• [x] I reviewed submitted code
• [ ] I added unit tests for my changes where possible
• [ ] I added a CHANGELOG entry if applicable

[Abhicodes-crypto]

Is there a limit on the file size that is uploaded to hyperswitch ?