Raise errors on all unsuccessful HTTP response codes

[main24]

Problem

Currently not all unsuccessful HTTP response codes are treated as unsuccessful response.
That leads to an error on parsing response body later in the flow.

Solution

• Raise error Vend::PaymentRequired on HTTP code 402 -- that's observable behaviour of Vend API;
• Raise the default error Vend::HttpError on all HTTP codes (including 0) other than 200..299.

[Copilot]

Pull Request Overview

This PR improves error handling for HTTP response codes by ensuring all unsuccessful status codes (outside 200-299) raise appropriate exceptions. Previously, only specific mapped error codes would raise exceptions, potentially causing parsing errors for unmapped unsuccessful responses.

• Adds PaymentRequired exception class for HTTP 402 responses
• Changes logic to raise exceptions for all non-2xx status codes, including code 0
• Refactors error handling logic into separate helper methods for better maintainability

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
lib/vend/exception.rb	Adds PaymentRequired exception class, updates error handling logic to catch all non-2xx codes, and refactors into helper methods
spec/vend/unit/exception_spec.rb	Comprehensive test updates covering successful responses, error code 0, unmapped error codes, and specific exception mappings

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[Copilot]

There's a typo in the error message. 'Something web wrong' should be 'Something went wrong'.

Suggested change

	let(:body) { 'Something web wrong' }
	let(:body) { 'Something went wrong' }