[FEATURE] payment-required header support in http_request tool

[rajuans]

Problem Statement

I would like Strands http_request tool to return "payment-required" header in the response so that plugin can utilize and inject payment related processing.

Payment-required header is sent by the endpoint server when they are behind paywall for x402Version 2 version. Here x402 specification: https://github.com/coinbase/x402/blob/main/specs/x402-specification-v2.md

Proposed Solution

Added header "payment-required" here.

Use Case

This will enable developing plugin for auto payment processing for x402 payment required header.

Alternatives Solutions

No response

Additional Context

No response

[rajuans]

Created a PR for this: strands-agents/tools#423