fix(select): floating label covers placeholder when when blurred (#27446)

Issue number: resolves #27201

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issue. -->

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## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

Selects with a floating label, no value, and a placeholder should have
the label cover the placeholder when blurred. One focus, the label
should translate to the top of the select, and the placeholder should be
visible.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- Floating label now covers the select and hides the placeholder when
the select is blurred, matching the `ion-input` and `ion-textarea`
behaviors.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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and migration path for existing applications below. -->


## Other information

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screenshots of how the component looks before and after the change. -->

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Co-authored-by: ionitron <hi@ionicframework.com>

core/src/components/textarea/test/label-placement/textarea.e2e.ts

@@ -179,6 +179,19 @@ configs().forEach(({ title, screenshot, config }) => {
       const textarea = page.locator('ion-textarea');
       expect(await textarea.screenshot()).toMatchSnapshot(screenshot(`textarea-placement-floating-no-value`));
     });
+    test('label should appear on top of the textarea when there is a placeholder and no value', async ({ page }) => {
+      await page.setContent(
+        `
+         <ion-textarea label="Standard" label-placement="floating" placeholder="Placeholder"></ion-textarea>
+       `,
+        config
+      );
+
+      const textarea = page.locator('ion-textarea');
+      expect(await textarea.screenshot()).toMatchSnapshot(
+        screenshot(`textarea-placement-floating-no-value-placeholder`)
+      );
+    });
     test('label should appear on top of the textarea when the textarea is focused', async ({ page }) => {
       await page.setContent(
         `