Update observability onboarding test to express state of the art (#17…

…4734)

## Summary

TLDR; This PR updates the cypress test suite that tests the custom
integration used to set up logs during onboarding.

The PR #171720 surfaced the fact
that this test suite isn't passing, especially given it doesn't run
unless a file with the observability onboarding plugin directory is
modified.

The most notable changes to the test suite, is opting to delete the
provided integration without verifying if it is installed. Why would we
do this one might ask;

- The existing API used to fetch integration packages expects packages
to have assets definition, and given this particular one doesn't have
assets so the request fails more details
[here](#174739).
- With the previous approach it required at least one call to determine
if the integration should be deleted, the only difference here is when
the test kicks off an attempt to delete an integration that doesn't
exist will be made once, but that's handled by setting setting the
cy.request `failOnStatusCode` option as false, so it doesn't error.
- it also unblocks the aforementioned PR

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### Risk Matrix

Delete this section if it is not applicable to this PR.

Before closing this PR, invite QA, stakeholders, and other developers to
identify risks that should be tested prior to the change/feature
release.

When forming the risk matrix, consider some of the following examples
and how they may potentially impact the change:

| Risk | Probability | Severity | Mitigation/Notes |

|---------------------------|-------------|----------|-------------------------|
| Multiple Spaces&mdash;unexpected behavior in non-default Kibana Space.
| Low | High | Integration tests will verify that all features are still
supported in non-default Kibana Space and when user switches between
spaces. |
| Multiple nodes&mdash;Elasticsearch polling might have race conditions
when multiple Kibana nodes are polling for the same tasks. | High | Low
| Tasks are idempotent, so executing them multiple times will not result
in logical error, but will degrade performance. To test for this case we
add plenty of unit tests around this logic and document manual testing
procedure. |
| Code should gracefully handle cases when feature X or plugin Y are
disabled. | Medium | High | Unit tests will verify that any feature flag
or plugin combination still results in our service operational. |
| [See more potential risk
examples](https://github.com/elastic/kibana/blob/main/RISK_MATRIX.mdx) |


### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)
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x-pack/plugins/observability_onboarding/e2e/cypress/e2e/logs/custom_logs/install_elastic_agent.cy.ts

@@ -623,7 +623,9 @@ describe('[Logs onboarding] Custom logs - install elastic agent', () => {
       cy.getByTestSubj('obltOnboardingExploreLogs').should('exist').click();
 
       cy.url().should('include', '/app/observability-log-explorer');
-      cy.get('button').contains('[Mylogs] mylogs').should('exist');
+      cy.get('[data-test-subj="datasetSelectorPopoverButton"]')
+        .contains('[Mylogs] mylogs', { matchCase: false })
+        .should('exist');
     });
   });
 });

x-pack/plugins/observability_onboarding/e2e/cypress/support/commands.ts

@@ -125,30 +125,17 @@ Cypress.Commands.add('deleteIntegration', (integrationName: string) => {
 
   cy.request({
     log: false,
-    method: 'GET',
+    method: 'DELETE',
     url: `${kibanaUrl}/api/fleet/epm/packages/${integrationName}`,
+    body: {
+      force: false,
+    },
     headers: {
       'kbn-xsrf': 'e2e_test',
+      'Elastic-Api-Version': '1',
     },
     auth: { user: 'editor', pass: 'changeme' },
     failOnStatusCode: false,
-  }).then((response) => {
-    const status = response.body.item?.status;
-    if (status === 'installed') {
-      cy.request({
-        log: false,
-        method: 'DELETE',
-        url: `${kibanaUrl}/api/fleet/epm/packages/${integrationName}`,
-        body: {
-          force: false,
-        },
-        headers: {
-          'kbn-xsrf': 'e2e_test',
-          'Elastic-Api-Version': '1',
-        },
-        auth: { user: 'editor', pass: 'changeme' },
-      });
-    }
   });
 });