Apply Limits to ReactiveCaching for Error Tracking

What does this MR do and why?

This MR adds a feature flag error_tracking_sentry_limit (rollout issue) to limit all Sentry responses (1 megabyte) and the same limit for ReactiveCaching functionlity of model ErrorTracking::ProjectErrorTrackingSetting.

Prior this commit only single Sentry response was checked (list_issues) now we are checking them all.

In a rare (rather by an attacker) case where the limit is exceeded we show the error message:

Failed to load errors from Sentry.

Contributes to #356448 (closed)

Screenshots or screen recordings

Within Limit	Limit exceeded	Limit exceeded during setup

How to set up and validate locally

1. Setup Sentry Integration with https://sentry.gitlab.net
2. Enable feature flag via Feature.enable(:error_tracking_sentry_limit)
3. List errors and view details ✅
4. Tweak RESPONSE_SIZE_LIMIT to 1.kilobyte
5. List errors and see the error message showing up ✅

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.