fix: querying by polymorphic join field relationTo with overrideAccess: false (#11999)

Previously, querying by polymorphic joins `relationTo` with
`overrideAccess: false` caused an error:
```
QueryError: The following paths cannot be queried: relationTo
```

As this field actually doesn't exist in the schema. Now, under condition
that the query comes from a polymorphic join we skip checking
`relationTo` field access.

test/joins/config.ts

@@ -222,6 +222,7 @@ export default buildConfigWithDefaults({
     },
     {
       slug: 'multiple-collections-parents',
+      access: { read: () => true },
       fields: [
         {
           type: 'join',
@@ -236,6 +237,7 @@ export default buildConfigWithDefaults({
     },
     {
       slug: 'multiple-collections-1',
+      access: { read: () => true },
       admin: { useAsTitle: 'title' },
       fields: [
         {
@@ -255,6 +257,7 @@ export default buildConfigWithDefaults({
     },
     {
       slug: 'multiple-collections-2',
+      access: { read: () => true },
       admin: { useAsTitle: 'title' },
       fields: [
         {

test/joins/int.spec.ts

@@ -1389,7 +1389,7 @@ describe('Joins Field', () => {
       expect(parent.children?.docs).toHaveLength(1)
       expect(parent.children.docs[0]?.value.title).toBe('doc-1')
 
-      // WHERE by _relationTo (join for specific collectionSlug)
+      // WHERE by relationTo (join for specific collectionSlug)
       parent = await payload.findByID({
         collection: 'multiple-collections-parents',
         id: parent.id,
@@ -1405,6 +1405,23 @@ describe('Joins Field', () => {
         },
       })
 
+      // WHERE by relationTo with overrideAccess:false
+      parent = await payload.findByID({
+        collection: 'multiple-collections-parents',
+        id: parent.id,
+        overrideAccess: false,
+        depth: 1,
+        joins: {
+          children: {
+            where: {
+              relationTo: {
+                equals: 'multiple-collections-2',
+              },
+            },
+          },
+        },
+      })
+
       expect(parent.children?.docs).toHaveLength(1)
       expect(parent.children.docs[0]?.value.title).toBe('doc-2')