test - code block font size should not be applied twiced

add a test with playwright to check that we don't modify code fontsize in a way that this is will get a different value for code inside pre than font-size of pre itself

tests/docs/playwright/html/code-font-size.qmd

@@ -0,0 +1,8 @@
+---
+title: Testing code font size
+format: html
+---
+
+```python
+1 + 1
+```

tests/integration/playwright/tests/html-themes.spec.ts

@@ -19,4 +19,14 @@ test('Dark theming toggle change to dark background ', async ({ page }) => {
   await page.locator("a.quarto-color-scheme-toggle").click();
   const locatr2 = await page.locator('div').filter({ hasText: 'Quarto Playground' }).first()
   await expect(locatr2).toHaveCSS('background-color', 'rgb(255, 0, 0)');
+});
+
+test('Code block font size did not change and still equals to pre size', async ({ page }) => {
+  await page.goto('./html/code-font-size.html');
+  const code = page.getByRole('code')
+  const pre = page.locator('pre')
+  const preFontSize = await pre.evaluate((element) =>
+    window.getComputedStyle(element).getPropertyValue('font-size'),
+  );
+  await expect(code).toHaveCSS('font-size', preFontSize);
 });