Swap to using integers for extended bounds in the data histogram aggregation

[kyle-sammons]

Summary

With the swap to using OpenSearch aggregation parsing in the main Astra app, we need to update the backend of this Grafana plugin to send over the time ranges for aggregations as integers, otherwise data histogram aggregations on the _timesinceepoch field will fail.

Demo

This demo creates a basic dashboard that uses a date histogram aggregation on the _timesinceepoch field, and tests out an alert on said dashboard:

Previous alerting behavior

New alerting behavior

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've written tests to cover the new code and functionality included in this PR.
• I've read, agree to, and signed the Contributor License Agreement (CLA).