Default to non-threaded export setting for the web

[adamscott]

As #91382 will fix most of the audio issues when exporting single-threaded, I think we should default to this setting for maximum compatibility.

It would mean, though, that existing exports would go from threaded to non-threaded without changing the default value. See #91623 (comment)

[Calinou]

This makes sense, considering most web projects won't benefit that much from having threads enabled once #91382 is merged. Threads enabled usually makes the most sense for projects that need to offload their own computation to threads (which is a relatively low number of web projects I can think of).

It would mean, though, that existing exports would go from threaded to non-threaded without changing the default value.

Default values are always stored in export presets, so this won't break existing export presets.

[akien-mga]

Makes sense to me. But should we wait for #91382 to be merged first before merging this too?

[adamscott]

Makes sense to me. But should we wait for #91382 to be merged first before merging this too?

Yes, we can.

[akien-mga]

Thanks!

[Faless]

Note: We need to also change the default for godot-cpp, which requires some work because we don't yet support platform defaults there.