fix: virtual relationship fields with select (#12266)

Continuation of https://github.com/payloadcms/payload/pull/12265.

Currently, using `select` on new relationship virtual fields:
```
const doc = await payload.findByID({
  collection: 'virtual-relations',
  depth: 0,
  id,
  select: { postTitle: true },
})
```
doesn't work, because in order to calculate `post.title`, the `post`
field must be selected as well. This PR adds logic that sanitizes the
incoming `select` to include those relationships into `select` (that are
related to selected virtual fields)

---------

Co-authored-by: Dan Ribbens <dan.ribbens@gmail.com>

test/database/int.spec.ts

@@ -1997,6 +1997,23 @@ describe('database', () => {
       expect(draft.docs[0]?.postTitle).toBe('my-title')
     })
 
+    it('should not break when using select', async () => {
+      const post = await payload.create({ collection: 'posts', data: { title: 'my-title-10' } })
+      const { id } = await payload.create({
+        collection: 'virtual-relations',
+        depth: 0,
+        data: { post: post.id },
+      })
+
+      const doc = await payload.findByID({
+        collection: 'virtual-relations',
+        depth: 0,
+        id,
+        select: { postTitle: true },
+      })
+      expect(doc.postTitle).toBe('my-title-10')
+    })
+
     it('should allow virtual field as reference to ID', async () => {
       const post = await payload.create({ collection: 'posts', data: { title: 'my-title' } })
       const { id } = await payload.create({
@@ -2129,6 +2146,26 @@ describe('database', () => {
       expect(doc.postCategoryTitle).toBe('1-category')
     })
 
+    it('should not break when using select 2x deep', async () => {
+      const category = await payload.create({
+        collection: 'categories',
+        data: { title: '3-category' },
+      })
+      const post = await payload.create({
+        collection: 'posts',
+        data: { title: '3-post', category: category.id },
+      })
+      const doc = await payload.create({ collection: 'virtual-relations', data: { post: post.id } })
+
+      const docWithSelect = await payload.findByID({
+        collection: 'virtual-relations',
+        depth: 0,
+        id: doc.id,
+        select: { postCategoryTitle: true },
+      })
+      expect(docWithSelect.postCategoryTitle).toBe('3-category')
+    })
+
     it('should allow to query by virtual field 2x deep', async () => {
       const category = await payload.create({
         collection: 'categories',