Metric threshold rule alert on no data appears unchecked in UI even if value is set to true

[ymao1]

For the metric threshold rule type, the option to "alert on no data" is disabled if no "group by" field is specified, but it defaults to true when the rule is created. This creates a confusing user experience because the field appears to be unchecked (false) even when the value is true so users would have to inspect the rule configuration to know what the actual configuration is

Disabled row in the UI where the option is unchecked. For this rule, the alertOnNoData rule param is true

[elasticmachine]

Pinging @elastic/obs-ux-management-team (Team:obs-ux-management)

[jasonrhodes]

Let's check to see if this mismatch appears with the other "alert if group disappears" value (this ticket references "alertOnNoData" which isn't tied to the "Alert me if a group stops reporting data" checkbox.

Bigger question is whether we should ever let this value be "true" if there are no groups. Having a disabled checkbox marked "true" when it has no effect on the rule is also somewhat confusing.

[jasonrhodes]

During refinement conversation, our recommendation is:

1. Move no data settings into a single "Advanced Settings" section
2. Do not disable the alert me if a group disappears box
3. Change default value of that field to "false" instead of "true"
4. Mention that this value is only relevant if a group is selected
5. Add a link to extensive advanced settings documentation page in the single advanced settings section, where we can explain these more thoroughly

@maciejforcone @vinaychandrasekhar would love your thoughts on this

[maryam-saeidi]

I created a PR to fix the issue mentioned in this ticket: #188402

I think we can improve this logic more, as mentioned by @jasonrhodes, but I don't know how much effort we want to put into the metric threshold rule that hopefully will be deprecated in v9.

Here is a documentation request for the custom threshold rule no data settings based on the new changes that @maciejforcone suggested: elastic/observability-docs#4068