[Security Solution] Fix flaky timeline pagination tests (elastic#173531)

## Summary

Fixes elastic#169413
elastic#169619

and colocates related tests cases.

Flaky TR pipeline:
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/4614

x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/pagination.cy.ts

@@ -24,39 +24,34 @@ import { hostsUrl } from '../../../urls/navigation';
 
 // Flaky on serverless
 const defaultPageSize = 25;
-// FLAKY: https://github.com/elastic/kibana/issues/169413
-describe.skip('Pagination', { tags: ['@ess', '@serverless'] }, () => {
-  before(() => {
-    cy.task('esArchiverLoad', { archiveName: 'timeline' });
-  });
 
+describe('Timeline Pagination', { tags: ['@ess', '@serverless'] }, () => {
   beforeEach(() => {
+    cy.task('esArchiverLoad', { archiveName: 'timeline' });
     login();
     visitWithTimeRange(hostsUrl('allHosts'));
     openTimelineUsingToggle();
     populateTimeline();
   });
 
-  after(() => {
+  afterEach(() => {
     cy.task('esArchiverUnload', 'timeline');
   });
 
-  it(`should have ${defaultPageSize} events in the page by default`, () => {
+  it(`should paginate records correctly`, () => {
+    // should have ${defaultPageSize} events in the page by default
     cy.get(TIMELINE_EVENT).should('have.length', defaultPageSize);
-  });
 
-  it('should be able to go to next / previous page', () => {
+    // should be able to go to next / previous page
     cy.get(`${TIMELINE_FLYOUT} ${TIMELINE_EVENTS_COUNT_NEXT_PAGE}`).first().click();
     cy.get(`${TIMELINE_FLYOUT} ${TIMELINE_EVENTS_COUNT_PREV_PAGE}`).first().click();
-  });
 
-  it(`should select ${defaultPageSize} items per page by default`, () => {
+    // should select ${defaultPageSize} items per page by default
     cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE).should('contain.text', defaultPageSize);
-  });
 
-  it('should be able to change items count per page with the dropdown', () => {
+    // should be able to change items count per page with the dropdown
     const itemsPerPage = 100;
-    cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE_BTN).first().click({ force: true });
+    cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE_BTN).first().click();
     cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE_OPTION(itemsPerPage)).click();
     cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE).should('not.have.text', '0');
     cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE)