[UI] Refactor tests (#13056)

Change manual API calls to setSettingState helper

src/frontend/tests/pui_forms.spec.ts

@@ -218,13 +218,7 @@ test('Forms - Keep form open option', async ({ browser }) => {
 test('Forms - DateTime Field', async ({ browser }) => {
   // The "started_datetime" / "finished_datetime" test-result fields are only
   // shown when the "TEST_STATION_DATA" global setting is enabled
-  const api = await createApi({});
-  const settingUrl = 'settings/global/TEST_STATION_DATA/';
-
-  const enableResponse = await api.patch(settingUrl, {
-    data: { value: 'true' }
-  });
-  expect(enableResponse.status()).toBe(200);
+  await setSettingState({ setting: 'TEST_STATION_DATA', value: true });
 
   const page = await doCachedLogin(browser, {
     user: stevenuser,
@@ -282,10 +276,7 @@ test('Forms - DateTime Field', async ({ browser }) => {
   await page.getByText('Test result updated').waitFor();
 
   // Restore the global setting to its default value
-  const disableResponse = await api.patch(settingUrl, {
-    data: { value: 'false' }
-  });
-  expect(disableResponse.status()).toBe(200);
+  await setSettingState({ setting: 'TEST_STATION_DATA', value: false });
 });
 
 // Test the "nested object" field type, via the "Initial Supplier" section