Improve max event limit count to be passed to frontend
## What is the issue
- The max limit for Cycle Analytics events is a hardcoded value in the [backend](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7743/diffs#41ee9fd9791b478528ebec731752d6731b628a05_8_8) and [frontend](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10179/diffs#324ed5beb395928ba56953ce830d36bfe6ff3648_0_9)
## Solution
- Pass the `MAX_EVENTS` to the frontend to be used in the `limit_warning_component.js`
## Reasons
- Improve the testability of limit warning component
- Reduce the chance these values get out of sync
## Related MRs
Add limit to the number of events showed in cycle analytics | gitlab-ce!7743
Resolve "Add event limit warning to all Cycle Analytics tabs" | gitlab-ce!10179
/cc @filipa @grzesiek
issue