Color Sampling for Vertex Colors in Grease Pencil's Draw Mode

Color sampling is a vital hotkey for painterly workflows. In almost every painting app, it is so frequently used that it's assigned a hotkey. Blender uses this ubiquitously in modes such as Texture Paint and Vertex Paint modes, with the hotkey S.

An example of of the S sampling hotkey from Texture Paint mode:

Grease Pencil allows for a vertex paint methodology in a painterly workflow, you would want to sample a color on the fly for a vertex color.

My proposal is that, when in Draw mode in Grease Pencil and Vertex Color is on, the S hotkey samples a color from the viewport.

There are several pathways to picking a vertex color right now, such as the Tint Tool, Vertex Paint mode, and using the Color Palette. However, they all lack the immediacy of a hotkey to temporarily color pick.

S would be the ideal hotkey, as it would follow the convention found in other Blender painting interfaces. But if this is reserved (for instance, if S might someday activate Scale the way that G can move strokes in the middle of using the Curve tool) it could still be added with a different hotkey.