[Alerting v2] [Rule authoring] Add compressed prop to flyout rule form fields

[yiannisnikolopoulos]

Closes elastic/rna-program#244

Summary

Applies EUI compressed density to all form input components when the rule form is rendered in flyout layout (layout === 'flyout'). The full-page layout is unaffected.

The change follows the pattern established in #260750: read layout from useRuleFormMeta() and conditionally apply flyout-specific props.

What changed

Shared utility components — added a compressed prop to the interface so callers can pass it down without these components reaching into context:

• NumberInput — forwarded to EuiFieldNumber via ...rest
• DurationInput — passed explicitly to NumberInput and EuiSelect
• LookbackWindow, RuleSchedule — forwarded via {...props} spread to DurationInput

Field components — each reads const { layout } = useRuleFormMeta() and passes compressed={layout === 'flyout'} to its EUI input:

• TagsField → EuiComboBox
• DescriptionField → EuiTextArea
• RecoveryTypeField → EuiSelect
• GroupFieldSelect → EuiComboBox
• TimeFieldSelect → EuiSelect
• ScheduleField / LookbackWindowField → threaded down to DurationInput
• AlertDelayField / RecoveryDelayField → EuiButtonGroup buttonSize ('compressed' in flyout, 's' in page)
• StateTransitionCountField → NumberInput
• StateTransitionTimeframeField → DurationInput

Excluded (no compressed prop in EUI): NameField (EuiInlineEditTitle), KindField (EuiCheckableCard), RunbookField (markdown modal).

Testing

• Added flyout layout smoke tests to all modified test files
• Created tags_field.test.tsx (was missing)

[macroscopeapp]

Approvability

Verdict: Needs human review

Mechanical UI change adding compressed styling prop to form fields in flyout layout - low risk and straightforward. However, all 27 files are owned by @elastic/rna-project-team and the author is not a code owner, so designated team review is appropriate.

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[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 0f1d2d7

Failed CI Steps

• Scout: [ platform / workflows_management ] plugin

Test Failures

• [job] [logs] Scout: [ platform / workflows_management ] plugin / local-serverless-security_complete - Workflow execution - Alert triggers - should trigger workflow from alert

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
alertingVTwo	280.7KB	281.3KB	+549.0B

cc @yiannisnikolopoulos