Desktop: Style is reformatted and gl-style-format is not used

[pathmapper]

When a style is exported with the online version, the style is formatted with gl-style-format.

This is useful for unification of styles, especially when making PRs to style repositories, see openmaptiles/osm-bright-gl-style#24.

When a style is modified with Maputnik Desktop, currently gl-style-format is not used and the style is reformatted somehow, see maputnik/osm-liberty#66.

Maybe we could add gl-style-format to Desktop or at least make sure that an already with gl-style-format formatted style is not altered when edited with Desktop.

@lukaswelte any thoughts?

[kylebarron]

As a follow up, it looks like format is only invoked when the style is exported.
https://github.com/maputnik/editor/blob/3c93c41de1e1a38bba288c13a41afd1d213defbf/src/components/modals/ExportModal.jsx#L40

So when Maputnik desktop is used with

maputnik --watch --file style.json

any edits aren't formatted, since the style is auto updated on change, and the Export button is never used.

[pathmapper]

With Maputnik Desktop v1.7.0 the style is formatted properly (#606).