[EDR Workflows] Enable Blocklist CY in MKI (elastic#197952)

Since adding this test file was tied to changes in Kibana, we initially
couldn’t enable it in the MKI. The MKI relies on a Kibana image built
from the main branch, and at that time, the necessary changes for these
tests to pass hadn’t yet been merged. Now that these updates are
included in the main branch, the Kibana image used in MKI has the
required changes, so we can proceed with enabling the tests.

Manual MKI run -
https://buildkite.com/elastic/kibana-serverless-security-solution-quality-gate-defend-workflows/builds/1545

x-pack/plugins/security_solution/public/management/cypress/e2e/artifacts/blocklist.cy.ts

@@ -41,7 +41,7 @@ const {
 describe(
   'Blocklist',
   {
-    tags: ['@ess', '@serverless', '@skipInServerlessMKI'], // @skipInServerlessMKI until kibana is rebuilt after merge
+    tags: ['@ess', '@serverless'],
   },
   () => {
     let indexedPolicy: IndexedFleetEndpointPolicyResponse;