Add optional segmentation metrics plots to MetricsPlotSink.

[Abdul-Mukit]

Description

Closes: #409
After completing training with RFDETRSegPreview, the plots in metrics_plot.png still only contain metrics related to BBox. Plots of segmentation metrics are missing.

Changes:

• If RFDETRSegPreview is trained, plot the masks-related metrics.
• If any other BBox-only models are being trained (e.g., RFDETRMedium ), plot only the BBox-related metrics.

Current behavior of MetricsPlotSink:
Even when training a RFDETRSegPreview, we only get plots for BBox metrics.

Updated behavior of MetricsPlotSink:

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How has this change been tested, please provide a testcase or example of how you tested the change?

Tested on Google Colab for both RFDETRMedium and RFDETRSegPreview.

Any specific deployment considerations

None

Docs

None

[Abdul-Mukit]

Hi @isaacrob-roboflow do you have any comments on this PR?
I am using this feature for my experiments. It would be helpful if this were part of the rfdeter repo.
Please let me know if you want any modifications. Thank you.