[MediaCapture Extensions] Fix background segmentation mask constraints
This CL fixes background segmentation mask constraints to be passed
to the imagecapture module and adds a web platform test to test
background segmentation mask constraints and settings.
Background segmentation mask feature is behind a flag:
chrome --enable-blink-features=MediaCaptureCameraControls
Intent to Prototype: https://groups.google.com/a/chromium.org/g/blink-dev/c/nWEqxi83rus
Spec: w3c/mediacapture-extensions#142
Explainer: https://github.com/riju/backgroundBlur/blob/main/explainer.md#background-segmentation-mask-api
Bug: 349939554
Change-Id: I1c11bd8919272147ed28f699a38dd8922cefc4c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5783519
Reviewed-by: Rijubrata Bhaumik rijubrata.bhaumik@intel.com
Commit-Queue: Eero Hakkinen eero.hakkinen@intel.com
Reviewed-by: Guido Urdaneta guidou@chromium.org
Cr-Commit-Position: refs/heads/main@{#1341202}