fix(types): use ButtonVariant & ButtonPresetTheme, fix playwright types

Fix "yarn typecheck":
```
$ yarn typecheck
yarn run v1.22.22
$ tsc --project ./tsconfig.json --noEmit
src/domain/headless-cms/components/__tests__/CmsPage.test.tsx:113:11 -
error TS2322: Type '"primary"' is not assignable to type
'ButtonVariant.Primary | ButtonVariant.Secondary | ButtonVariant.Success
| ButtonVariant.Danger | ButtonVariant.Clear | undefined'.

113           loadMoreButtonVariant: 'primary',
              ~~~~~~~~~~~~~~~~~~~~~

src/domain/headless-cms/components/__tests__/CmsPage.test.tsx:114:11 -
error TS2322: Type '"coat"' is not assignable to type 'ButtonPresetTheme
| ButtonTheme | undefined'.

114           loadMoreButtonTheme: 'coat',
              ~~~~~~~~~~~~~~~~~~~

src/playwright/tests/search.spec.ts:55:41 - error TS2345: Argument of
type '"Detaljerad sökning"' is not assignable to parameter of type
'SearchButton'.

55     await frontPageSv.clickSearchButton('Detaljerad sökning');
                                           ~~~~~~~~~~~~~~~~~~~~

src/playwright/tests/search.spec.ts:71:41 - error TS2345: Argument of
type '"Advanced search"' is not assignable to parameter of type
'SearchButton'.

71     await frontPageEn.clickSearchButton('Advanced search');
                                           ~~~~~~~~~~~~~~~~~
```

Refs: PT-453

Author: karisal-anders

src/domain/headless-cms/components/__tests__/CmsPage.test.tsx

@@ -3,6 +3,7 @@ import {
   ConfigProvider as RHHCConfigProvider,
   defaultConfig as rhhcDefaultConfig,
 } from '@city-of-helsinki/react-helsinki-headless-cms';
+import { ButtonPresetTheme, ButtonVariant } from 'hds-react';
 import * as React from 'react';
 
 import {
@@ -110,8 +111,8 @@ test('renders with sidebar layout when sidebar has content', async () => {
           openInExternalDomainAriaLabel: 'Avautuu uudella sivustolla.',
         },
         customCopy: {
-          loadMoreButtonVariant: 'primary',
-          loadMoreButtonTheme: 'coat',
+          loadMoreButtonVariant: ButtonVariant.Primary,
+          loadMoreButtonTheme: ButtonPresetTheme.Coat,
         },
         internalHrefOrigins,
         utils: {

src/playwright/pages/searchCapable.page.ts

@@ -7,7 +7,10 @@ type ZeroToTwoYears = '0-2 vuotiaat' | '0-2 år' | '0-2 years';
 type TargetGroupOption = ZeroToTwoYears;
 type SearchOption = TargetGroupOption;
 type SearchEvents = 'Hae tapahtumia' | 'Sök evenemang' | 'Search events';
-type AdvancedSearch = 'Tarkennettu haku' | 'Redigera sökning' | 'Edit search';
+type AdvancedSearch =
+  | 'Tarkennettu haku'
+  | 'Detaljerad sökning'
+  | 'Advanced search';
 type SearchButton = SearchEvents | AdvancedSearch;
 type SearchTextBox = SearchEvents | TargetGroupButton;
 type TargetGroupField = TargetGroupButton;