Changing Custom Font's Dynamic Font's Font Data's Font Path doesn't refresh font on GUI node

[kuhnchris]

Godot version:
3.3-rc6 (custom, Godot Engine v3.3.rc.custom_build.9a5776cd1 - https://godotengine.org )

OS/device including version:
ArchLinux
OpenGL ES 3.0 Renderer: AMD RENOIR (DRM 3.40.0, 5.11.6-arch1-1, LLVM 11.1.0)
OpenGL ES Batching: ON

Issue description:
Changing the font path (i.e. changing the font) in a RichTextLabel doesn't refresh the display

Steps to reproduce:

• Add RichTextLabel
• Enter some text
• Add a Custom Fonts > Normal Fonts (New DynamicFont) > Font > Font Data (New DynamicFontData) > Font Path Object, i.e. select a custom font
• Text gets properly refresh with new font
  
• Go to the Font Data and change Font Path, i.e. change to a different font:
  
• The font is not changed!
  
• Changing font size or other parameters does not load the proper font in, so it is "cached"
  
• Closing and reopening the scene fixes it, but it should be like this directly after changing the font!
  

Minimal reproduction project:
godot-33rc6-dynfontpath.zip

[Calinou]

Duplicate of #27106 (same cause).