feat(richtext-lexical): add useAsTitle to the popup links label (#8718)

Now we show not only the collection being linked to, but also the
document title:

![image](https://github.com/user-attachments/assets/5ba5713a-b051-4f11-ae2a-d5b50a25966b)

Previously this example was just displayed as: `Linked to Users`

- I've added a loading state in case the request is slow (verified with
fake slow connection).
- I have verified that if the `useAsTitle` is not defined, it correctly
fallbacks to the id

Please let me know if the same needs to be done with Slate.

---------

Co-authored-by: Alessio Gravili <alessio@gravili.de>

test/fields/collections/RichText/e2e.spec.ts

@@ -238,12 +238,15 @@ describe('Rich Text', () => {
 
     test('should only list RTE enabled collections in link drawer', async () => {
       await navigateToRichTextFields()
+      await wait(1000)
 
       await page.locator('.rich-text__toolbar button:not([disabled]) .link').first().click()
 
       const editLinkModal = page.locator('[id^=drawer_1_rich-text-link-]')
       await expect(editLinkModal).toBeVisible()
 
+      await wait(1000)
+
       await editLinkModal.locator('label[for="field-linkType-internal-2"]').click()
       await editLinkModal.locator('.relationship__wrap .rs__control').click()
 
@@ -255,6 +258,7 @@ describe('Rich Text', () => {
 
     test('should only list non-upload collections in relationship drawer', async () => {
       await navigateToRichTextFields()
+      await wait(1000)
 
       // Open link drawer
       await page
@@ -262,7 +266,7 @@ describe('Rich Text', () => {
         .first()
         .click()
 
-      await wait(300)
+      await wait(1000)
 
       // open the list select menu
       await page.locator('.list-drawer__select-collection-wrap .rs__control').click()
@@ -277,12 +281,15 @@ describe('Rich Text', () => {
       const linkText = 'link'
       const value = 'test value'
       await navigateToRichTextFields()
+      await wait(1000)
+
       const field = page.locator('.rich-text', {
         has: page.locator('#field-richTextCustomFields'),
       })
       // open link drawer
       const button = field.locator('button.rich-text__button.link')
       await button.click()
+      await wait(1000)
 
       // fill link fields
       const linkDrawer = page.locator('[id^=drawer_1_rich-text-link-]')
@@ -292,11 +299,13 @@ describe('Rich Text', () => {
       const input = fields.locator('#field-fields__customLinkField')
       await input.fill(value)
 
-      await wait(300)
+      await wait(1000)
 
       // submit link closing drawer
       await linkDrawer.locator('button[type="submit"]').click()
       const linkInEditor = field.locator(`.rich-text-link >> text="${linkText}"`)
+      await wait(300)
+
       await saveDocAndAssert(page)
 
       // open modal again