Fix broken Semantic Scholar API

[hornlukas]

Description

Closes #104

This PR addresses the broken Semantic Scholar API link and improves the handling of unauthenticated requests to mitigate 429 Too Many Requests errors.

Changes

• Fixed API Link: Updated the URL to the correct endpoint.
• Retry Strategy: Implemented a retry mechanism using urllib3 to handle transient failures (3 retries, 1s backoff).
• Tests: Adapted existing tests to reflect the API updates.

Context & Results

The current global rate limit for unauthenticated requests is 1000 requests per second. Since this is a shared global limit, requests are often rejected with 429s.

I tested this locally:

• The retry strategy significantly improves success rates.
• However, due to the global limit, occasional failures may still occur.
• Increasing retries/backoff further did not yield better results in my tests.

Recommendation

For consistent reliability, it is highly recommended to use an API key for authenticated requests (1 req/s) rather than relying on the unauthenticated global pool.

Discussion

I am open to suggestions regarding the retry configuration if others find more optimal settings.