[Synthetics] Unskip Synthetics Serverless Enablement API tests (#180199)

## Summary

Fixes #180108.

Previously these tests failed against MKI. This should resolve the
problem as we're no longer trying to use `system_indices_superuser`,
which doesn't exist in MKI environments.

x-pack/test_serverless/api_integration/test_suites/observability/synthetics/synthetics_enablement.ts

@@ -42,8 +42,6 @@ export default function ({ getService }: FtrProviderContext) {
   };
 
   describe('SyntheticsEnablement', function () {
-    // failsOnMKI, see https://github.com/elastic/kibana/issues/180108
-    this.tags(['failsOnMKI']);
     const svlUserManager = getService('svlUserManager');
     const svlCommonApi = getService('svlCommonApi');
     const supertestWithoutAuth = getService('supertestWithoutAuth');
@@ -81,7 +79,7 @@ export default function ({ getService }: FtrProviderContext) {
     }
 
     describe('[PUT] /internal/uptime/service/enablement', () => {
-      const roles: RoleName[] = ['admin', 'editor', 'system_indices_superuser', 'viewer'];
+      const roles: RoleName[] = ['admin', 'editor', 'viewer'];
 
       roles.forEach((role) => {
         it(`${role} role has appropriate permissions for API keys`, async () => {
@@ -91,7 +89,7 @@ export default function ({ getService }: FtrProviderContext) {
 
           const { body } = await enablementPut(role);
 
-          if (['system_indices_superuser', 'admin'].indexOf(role) !== -1) {
+          if (['admin'].indexOf(role) !== -1) {
             expect(body).to.eql(ALL_ENABLED);
           } else {
             expect(body).to.eql({
@@ -166,21 +164,21 @@ export default function ({ getService }: FtrProviderContext) {
       beforeEach(async () => {
         const apiKeys = await getApiKeys();
         if (apiKeys.length) {
-          await enablementDelete('system_indices_superuser');
+          await enablementDelete();
         }
       });
       it('admin can delete api key', async () => {
-        await enablementPut('system_indices_superuser');
+        await enablementPut();
 
-        const delResponse = await enablementDelete('system_indices_superuser');
+        const delResponse = await enablementDelete();
 
         expect(delResponse.body).eql({});
         const apiResponse = await enablementPut();
 
         expect(apiResponse.body).eql(ALL_ENABLED);
       });
 
-      it('with an editor user', async () => {
+      it('editor user cannot delete API key', async () => {
         await enablementPut();
         await enablementDelete('editor', 403);
         const apiResponse = await enablementPut('editor');
@@ -192,6 +190,19 @@ export default function ({ getService }: FtrProviderContext) {
           isValidApiKey: true,
         });
       });
+
+      it('viewer user cannot delete API key', async () => {
+        await enablementPut();
+        await enablementDelete('viewer', 403);
+        const apiResponse = await enablementPut('viewer');
+        expect(apiResponse.body).eql({
+          areApiKeysEnabled: true,
+          canManageApiKeys: false,
+          canEnable: false,
+          isEnabled: true,
+          isValidApiKey: true,
+        });
+      });
     });
   });
 }