[color] map sketch plugin to update color variables instead of layer styles

[laurenmrice]

Sketch plugin (color):

• We want the plugin to sync color variables instead of shared layer styles in sketch.
• We added an additional level of color variables as the base colors that will update our layer styles automatically because they are linked.
  

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As-is

Github -> Plugin -> Sync shared layer styles -> (Updates layer style hex values)

To-be

Github -> Plugin -> Sync color variables -> (Updates color variable hex values)