Make project setting export respect to convert_text_resources_to_binary

[jsjtxietian]

Fixes #90981

Tested locally it seems all is ok since we use _load_settings_text_or_binary("res://project.godot", "res://project.binary") to load the setting all the time.

[AThousandShips]

Glanced at the code for the project settings and it doesn't seem like it expects binary explicitly in exports, I'd argue the original issue comes from invalid documentation references rather than faulty code, but dont think it hurts to respect this setting here, though I also don't necessarily think there's any reason to not store it as binary

But for my part I'd say to go with this

A second pair of eyes from someone would be good though on the relevant area

[jsjtxietian]

what a nice pr id, 90999

[akien-mga]

Discussed briefly with @reduz, it's not clear whether we should actually make this change. Project Settings aren't a resource so technically they're not related to that setting.

We need to assess what's the use case for exporting the project.godot file as is, and whether this setting (or a new one) is the right way to enable it. If the problem is only that the documentation was misleading, we can fix the documentation instead.