fix(richtext-lexical): enable select inputs with ctrl+a or cmd+a (#12453)

Fixes #6871

To review this PR, use `pnpm dev lexical` and the auto-created document
in the `lexical fields` collection. Select any input within the blocks
and press `cmd+a`. The selection should contain the entire input.

I made sure that `cmd+a` still works fine inside the editor but outside
of inputs.

test/lexical/collections/_LexicalFullyFeatured/e2e.spec.ts

@@ -62,6 +62,24 @@ describe('Lexical Fully Featured', () => {
     const paragraph = lexical.editor.locator('> p')
     await expect(paragraph).toHaveText('')
   })
+
+  test('ControlOrMeta+A inside input should select all the text inside the input', async ({
+    page,
+  }) => {
+    const lexical = new LexicalHelpers(page)
+    await lexical.editor.first().focus()
+    await page.keyboard.type('Hello')
+    await page.keyboard.press('Enter')
+    await lexical.slashCommand('block')
+    await page.locator('#field-someText').first().focus()
+    await page.keyboard.type('World')
+    await page.keyboard.press('ControlOrMeta+A')
+    await page.keyboard.press('Backspace')
+    const paragraph = lexical.editor.locator('> p').first()
+    await expect(paragraph).toHaveText('Hello')
+    await expect(page.getByText('World')).toHaveCount(0)
+  })
+
   test('text state feature', async ({ page }) => {
     await page.keyboard.type('Hello')
     await page.keyboard.press('ControlOrMeta+A')