Fix passing empty mask to SEGS controlnet preprocessors

[fAIseh00d]

Hi!

I encountered an issue when using xinsir's SDXL union controlnet for inpainting with SEGS.

There were two issues:

1. Wrong inpaint fill color for xinsir union controlnet.
   Fixed here
2. Not passing cropped mask from SEGS to controlnet preprocessors, resulting in fully black filled controlnet image when using Inpaint Preprocessor Provider (SEGS).
   Fixed in this PR.

Before:

After:

Be aware that this is a quick fix, and I have not had time to check every possible combination of controlnets and preprocesors.
Also my approach might be suboptimal, and I'm open to improvement suggestions.

Here's the test workflow:
workflow (6).json

[fAIseh00d]

My bad, turns out that the mask is already passed to preprocessor but only if noise_mask is enabled.