[Discover] Revert data table row height to 3 by default (elastic#169724)

## Summary

This PR reverts the changes from elastic#164218 that updated the default
Discover grid row height to "auto", and changes it back to "3".

### Checklist

- [ ] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [ ]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] Any UI touched in this PR is usable by keyboard only (learn more
about [keyboard accessibility](https://webaim.org/techniques/keyboard/))
- [ ] Any UI touched in this PR does not create any new axe failures
(run axe in browser:
[FF](https://addons.mozilla.org/en-US/firefox/addon/axe-devtools/),
[Chrome](https://chrome.google.com/webstore/detail/axe-web-accessibility-tes/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US))
- [ ] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [ ] This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))
- [ ] This was checked for [cross-browser
compatibility](https://www.elastic.co/support/matrix#matrix_browsers)

### 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)

packages/kbn-unified-data-table/src/constants.ts

@@ -20,7 +20,7 @@ export const ROWS_PER_PAGE_OPTIONS = [10, 25, 50, DEFAULT_ROWS_PER_PAGE, 250, 50
 export const ROWS_HEIGHT_OPTIONS = {
   auto: -1,
   single: 0,
-  default: -1,
+  default: 3,
 };
 export const defaultRowLineHeight = '1.6em';
 export const defaultMonacoEditorWidth = 370;

packages/kbn-unified-data-table/src/hooks/use_row_heights_options.test.tsx

@@ -11,6 +11,8 @@ import { Storage } from '@kbn/kibana-utils-plugin/public';
 import { LocalStorageMock } from '../../__mocks__/local_storage_mock';
 import { useRowHeightsOptions } from './use_row_heights_options';
 
+const CONFIG_ROW_HEIGHT = 3;
+
 describe('useRowHeightsOptions', () => {
   test('should apply rowHeight from savedSearch', () => {
     const { result } = renderHook(() => {
@@ -30,7 +32,7 @@ describe('useRowHeightsOptions', () => {
         storage: new LocalStorageMock({
           ['discover:dataGridRowHeight']: {
             previousRowHeight: 5,
-            previousConfigRowHeight: -1,
+            previousConfigRowHeight: 3,
           },
         }) as unknown as Storage,
         consumer: 'discover',
@@ -50,7 +52,7 @@ describe('useRowHeightsOptions', () => {
     });
 
     expect(result.current.defaultHeight).toEqual({
-      lineCount: 3,
+      lineCount: CONFIG_ROW_HEIGHT,
     });
   });
 
@@ -59,15 +61,17 @@ describe('useRowHeightsOptions', () => {
       return useRowHeightsOptions({
         storage: new LocalStorageMock({
           ['discover:dataGridRowHeight']: {
-            previousRowHeight: 5,
-            // different from uiSettings (config), now user changed it to -1, but prev was 4
+            previousRowHeight: 4,
+            // different from uiSettings (config), now user changed it to 3, but prev was 4
             previousConfigRowHeight: 4,
           },
         }) as unknown as Storage,
         consumer: 'discover',
       });
     });
 
-    expect(result.current.defaultHeight).toEqual('auto');
+    expect(result.current.defaultHeight).toEqual({
+      lineCount: CONFIG_ROW_HEIGHT,
+    });
   });
 });

src/plugins/discover/server/ui_settings.ts

@@ -287,7 +287,7 @@ export const getUiSettings: (docLinks: DocLinksServiceSetup) => Record<string, U
     name: i18n.translate('discover.advancedSettings.params.rowHeightTitle', {
       defaultMessage: 'Row height in the Document Explorer',
     }),
-    value: -1,
+    value: 3,
     category: ['discover'],
     description: i18n.translate('discover.advancedSettings.params.rowHeightText', {
       defaultMessage:

test/functional/apps/discover/group2/_data_grid_row_height.ts

@@ -45,12 +45,12 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
       expect(rows.length).to.be.above(0);
 
       await dataGrid.clickGridSettings();
-      expect(await dataGrid.getCurrentRowHeightValue()).to.be('Auto fit');
+      expect(await dataGrid.getCurrentRowHeightValue()).to.be('Custom');
     });
 
     it('should allow to change row height', async () => {
       await dataGrid.clickGridSettings();
-      expect(await dataGrid.getCurrentRowHeightValue()).to.be('Auto fit');
+      expect(await dataGrid.getCurrentRowHeightValue()).to.be('Custom');
 
       await dataGrid.changeRowHeightValue('Single');