No FolderPage for Folders that NEVER contained a file but did contain subfolders.

[MNielson]

Describe the bug
No FolderPage is generated for a Folder that contains (and has never contained) a file. That is, if you create the folders and files content/foo/bar/file.md the FolderPage foo/bar will exist but the FolderPage foo/ will not exist.
Creating a file content/foo/dummy.md will result in FolderPage foo/ being created, even if dummy.md is later deleted.

To Reproduce
Steps to reproduce the behavior:

1. Go to your content folder.
2. Create never before created subfolder dummy_1
3. Create never before created subfolder dummy_2 as a subfolder of dummy_1
4. Create SomeFile.md in content/dummy_1/dummy_2
5. Build and serve Quartz
6. Go to http://localhost:8080/dummy_1/dummy_2 (it should exist and show SomeFile.md)
7. Go to http://localhost:8080/dummy_1
8. See error 404

Additional steps:
9. Create SomeOtherFIle.md in content/dummy_1
10. Delete SomeOtherFIle.md in content/dummy_1
11. 7. Go to http://localhost:8080/dummy_1 (it should exist now)

Expected behavior
On Step 7, the FolderPage for dummy_1 should be shown (and should have been created at Step 5 I'm guessing)

Screenshots and Source

Desktop (please complete the following information):

• Quartz Version: v4.2.3
• node Version: v20.12.1
• npm version: 10.5.0
• OS: Windows 10 Pro
• Browser Version 123.0.6312.122