[Feature] Make ServiceMonitor scrape_interval and scrape_timeout optional in helm chart

[bruksnys]

Problem Statement

We prefer to use global values for all of our ServiceMonitors since it greatly simplifies the maintenance and allows us to have consistent scrape intervals that play well with various other metrics in our observability stack and return consistent results when comparing them using promql rate() function.

Solution Description

By modifying ServiceMonitor resource templates to allow for empty values - global scrape_interval and scrape_timeout values would be respected. Then, if an override is desired, operator could simply specify these values.

Alternatives

No response

Additional Context

At the moment scrape_interval and scrape_timeout values for the ServiceMonitor resource are set by default to 30s and 25s respectively here:
https://github.com/kyverno/kyverno/blob/main/charts/kyverno/values.yaml#L1220-L1223

If unspecified - these values would default to globals. Helm templates currently do not support having these values as undefined and thus always set a scrape_timeout which might be different from the global defaults.

Slack discussion

No response

Research

• I have read and followed the documentation AND the troubleshooting guide.
• I have searched other issues in this repository and mine is not recorded.

[welcome]

Thanks for opening your first issue here! Be sure to follow the issue template!