feat: improve rate limiter

[Litarnus]

Improves how we handle rate limits to align it with the specs and fix subtle bugs:

1. A shorter duration from a second request could overwrite the longer duration obtained previously. This is a violation of the specification. Always keep the maximum rate limit if multiple rate limits reference the same category. If a new rate limit is shorter than an already stored rate limit, then keep the longer one.
2. 429 without headers ignored rate limits, now it applies the default.
3. Improved handling for decimal durations

Reference: https://develop.sentry.dev/sdk/foundations/transport/rate-limiting/