Fixed related permissions query not considering drafts

Page-related items added on drafts could be visible in certain scenarios
since the applied permissions query filters would not consider
page draft visibility.
This commit alters queries on related items to apply such filtering.

Included test to cover API scenario.
Thanks to @haxatron for reporting.

tests/Api/AttachmentsApiTest.php

@@ -224,6 +224,29 @@ class AttachmentsApiTest extends TestCase
         unlink(storage_path($attachment->path));
     }
 
+    public function test_attachment_not_visible_on_other_users_draft()
+    {
+        $this->actingAsApiAdmin();
+        $editor = $this->getEditor();
+
+        /** @var Page $page */
+        $page = Page::query()->first();
+        $page->draft = true;
+        $page->owned_by = $editor;
+        $page->save();
+        $this->regenEntityPermissions($page);
+
+        $attachment = $this->createAttachmentForPage($page, [
+            'name'  => 'my attachment',
+            'path'  => 'https://example.com',
+            'order' => 1,
+        ]);
+
+        $resp = $this->getJson("{$this->baseEndpoint}/{$attachment->id}");
+
+        $resp->assertStatus(404);
+    }
+
     public function test_update_endpoint()
     {
         $this->actingAsApiAdmin();