feat: handle rate limit exceeded scenario in HttpTransport

[Nahrawene-ben-hmida]

📜 Description

Pull Request Description: Improve Error Handling for Rate Limits in HttpTransport

Changes Made

1. Added QuotaExceededException:

   • Introduced a new custom exception (QuotaExceededException) to signal explicitly when a rate limit is reached (HTTP status code 429).
   • Simplifies the handling of rate-limiting scenarios programmatically for users of the library.

2. Updated send Method:

   • Added a check for HTTP status code 429 in the send method.
   • Throws the newly created QuotaExceededException when the rate limit is exceeded.

3. Improved Error Feedback:

   • Ensures errors caused by rate limits are clearly communicated.
   • Aligns with Sentry's goal of providing better transparency and usability for developers.

Motivation

The current implementation does not make it straightforward to identify and handle rate-limiting errors. This improvement introduces an explicit mechanism to manage such cases, enhancing the developer experience and making the library more robust.

Testing

• Validated that the QuotaExceededException is thrown correctly when a 429 status code is received.
• Ensured existing behavior remains consistent for other HTTP status codes.

Impact

• Fully backward-compatible.
• Improves the error-handling ergonomics for developers using the Sentry Dart SDK.

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📝 Checklist

• I reviewed the submitted code.
• I added tests to verify changes.
• No new PII added, or the SDK only sends newly added PII if sendDefaultPii is enabled.
• I updated the documentation if needed.
• All tests are passing.
• No breaking changes.

[melWiss]

thanks for pushing this through, our team is desperate to have this quickly