[IO-1138] Semantic Mask colour map fix

[Nathanjp91]

Fix to the mapping of class colour mapping with semantic mask exports. Existing behaviour creates a new colour map for each file, leading to an issue where multiple file exports that have a mixture of classes between files get the wrong colour assigned to them. New logic pulls the colour from the category dictionary which is populated with the entire exports list of classes

Changelog

Fix for class colour mapping in csv for semantic masks

[linear]

IO-1138 BUG: The team at Horizon Surgical have reported an issue with what they see on the color_mapping.csv versus their PNG masks

BUG submission from: Muata Hunt
Summary (describe an issue):
The team at Horizon Surgical have reported an issue with what they see on the color_mapping.csv versus their PNG masks.

According to the team, the RGB values on the color_mapping.csv they've exported for at least 2 of their datasets don't match the colors for the corresponding classes on the PNG mask files. It's worth noting that this issue has only been reported on their V1 datasets thus far. .

I'll include the exported color_mapping.csv for each dataset below.
Share Loom/Screenshots with Console/Network opened:
N/A
Darwin affected version
V2
Environment (production/staging; browser and OS version)
V1 datasets on V2 account
Impact
Single (only 1 customer is impacted)
Priority
🔴 SWAT Urgent - an urgent problem that blocks users
Steps to reproduce
Note: I was not able to reproduce this on V1 or V2 datasets.

1. Create a few polygon annotations on an image.
2. Export the image as a semantic mask (PNG).
3. Download the export and open the CSV and mask file.
4. Google the RGB value and compare it the color observe in the mask file.
   Expected Behaviour
   Mask colors and the RGB values in the exported CSV should match.
   Team & Dataset Link
   Team - https://darwin.v7labs.com/super_admin/teams/2558
   Dataset - https://darwin.v7labs.com/datasets/529089/dataset-management and https://darwin.v7labs.com/datasets/619437/dataset-management
   Intercom ticket
   https://app.intercom.com/a/inbox/pb9z3asr/inbox/admin/5720549/conversation/204599?view=List

[NPatel1980]

QA passed, colour mapping on PNG now matches the RGB values listed on the CSV