Fix overwrite of manual changes in export_presets.cfg when export dialog is opened
Fix overwrite of manual changes in export_presets.cfg when export dialog is opened

Ensures that behavior when export_presets.cfg file is edited manually
while editor is running remains identical to before commit 44094b0.

(cherry picked from commit 4a7c19e71902bfa9effbd4e22484c4af0963b1bc)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot