test(playwright): do not check desktop viewports by default (#25222)

core/playwright.config.ts

@@ -7,22 +7,27 @@ expect.extend(matchers);
 
 const projects = [
   {
-    name: 'chromium',
-
+    /**
+     * This is really just desktop Firefox
+     * but with a mobile viewport.
+     */
+    name: 'Mobile Firefox',
     use: {
-      ...devices['Desktop Chrome'],
+      browserName: 'firefox',
+      /**
+       * This is the Pixel 5 configuration.
+       * We can't use devices['Pixel 5']
+       * because the "isMobile" option is
+       * not supported on Firefox.
+       */
+      viewport: {
+        width: 393,
+        height: 727
       },
-  },
-  {
-    name: 'firefox',
-    use: {
-      ...devices['Desktop Firefox'],
-    },
-  },
-  {
-    name: 'webkit',
-    use: {
-      ...devices['Desktop Safari'],
+      screen: {
+        width: 393,
+        height: 851
+      }
     },
   },
   {

core/src/components/datetime/test/basic/datetime.e2e.ts

@@ -6,6 +6,7 @@ test.describe('datetime: selecting a day', () => {
   const testHighlight = async (page: E2EPage, datetimeID: string) => {
     const today = new Date();
     await page.goto('/src/components/datetime/test/basic');
+    await page.setIonViewport();
 
     const todayBtn = page.locator(
       `#${datetimeID} .calendar-day[data-day='${today.getDate()}'][data-month='${today.getMonth() + 1}']`