Serverless Observability project failing test: "Search source Alert should show time field validation error"

[lukasolson]

Describe the bug:

Serverless Observability project search rule creation allows creating rule without time-based index pattern

Steps to reproduce:

1. Create a data view that has no time field
2. Open Discover in an Observability project
3. Click "Alerts" then "Create custom threshold rule"
4. Make sure the data view without a time field is selected (notice the error message flickering)
5. Save the alert

Expected behavior:

An error & not being able to save the alert.

Screenshots (if relevant):

Here's a video showing the expected behavior (from Discover, not being able to save the alert):

Screen.Recording.2024-12-04.at.9.30.48.PM.mov

Here's what happens in the observability project:

Screen.Recording.2024-12-04.at.9.29.45.PM.mov

Any additional context:

This came up as part of #196443 which re-enables some tests that were previously skipped. This test started failing (because it seems to be an actual bug):

kibana/x-pack/test_serverless/functional/test_suites/common/discover_ml_uptime/discover/search_source_alert.ts

Lines 430 to 458 in cc4367f

	it('should show time field validation error', async () => {
	await PageObjects.common.navigateToApp('discover');
	await PageObjects.discover.waitUntilSearchingHasFinished();
	await dataViews.switchToAndValidate(SOURCE_DATA_VIEW);
	await PageObjects.timePicker.setCommonlyUsedTime('Last_15 minutes');
	await openDiscoverAlertFlyout();
	await defineSearchSourceAlert(RULE_NAME);
	await testSubjects.click('selectDataViewExpression');
	await testSubjects.existOrFail('indexPattern-switcher--input');
	await testSubjects.click('indexPattern-switcher--input');
	const input = await find.activeElement();
	// search-source-alert-output index does not have time field
	await input.type('search-source-alert-o*');
	await testSubjects.existOrFail('explore-matching-indices-button');
	await testSubjects.click('explore-matching-indices-button');
	await retry.waitFor('selection to happen', async () => {
	const dataViewSelector = await testSubjects.find('selectDataViewExpression');
	return (await dataViewSelector.getVisibleText()) === 'DATA VIEW\nsearch-source-alert-o*';
	});
	await testSubjects.click('saveRuleButton');
	const errorElem = await testSubjects.find('esQueryAlertExpressionError');
	const errorText = await errorElem.getVisibleText();
	expect(errorText).to.eql('Data view should have a time field.');
	});

[elasticmachine]

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

[elasticmachine]

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

[maryam-saeidi]

Just to double-check, are you sure the selected data view does not have a time field? How did you create that data view?

We show the following error despite not disabling the save button:

[lukasolson]

Updated the original issue to describe this is limited to serverless observability (probably related to #198987)