Adjust error message for rate limits reached

**Problem**: We're currently displaying a timeout error message when running into rate limits as a result of refreshing a dashboard multiple times within a short timeframe. This is misleading and the suggested solution (reducing the time frame) doesn't make sense in this case.

**Proposed solution**: Update the error message for this case to inform the customer that a rate limit has been reached. "Rate limit reached. Please try again later." If we can be more specific about the timeframe, even better.

Related issue: https://www.notion.so/sentry/Dashboards-Widget-Timeouts-1138b10e4b5d8079ba15dd05d3a82a3e

Start by tracing the dashboard refresh timeout and rate-limit handling described in the issue, using the related Dashboards Widget Timeouts issue for context. Done means the affected case clearly reports that a rate limit was reached, with a more specific timeframe if available, instead of displaying a timeout message.

Written by the indexing model from the issue text.