Add RectLight to pprint value type dispatch

- Add RectLight to CASE_GPRIM_LIST macro in value-pprint.cc
- This fixes "VALUE_PPRINT: TODO: (type: RectLight)" output
- Remove usdlux_*.usda from KNOWN_FAILURES as they now pass roundtrip

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/value-pprint.cc

@@ -773,6 +773,7 @@ namespace value {
   __FUNC(DiskLight)             \
   __FUNC(DistantLight)          \
   __FUNC(CylinderLight)         \
+  __FUNC(RectLight)             \
   __FUNC(SkelRoot)              \
   __FUNC(Skeleton)              \
   __FUNC(SkelAnimation)         \

tests/usda/roundtrip-runner.py

@@ -11,9 +11,6 @@ import subprocess
 # Known failing files - these have known issues with roundtrip
 # that should be fixed in the future
 KNOWN_FAILURES = [
-    # UsdLux types not fully supported in pprinter (outputs "VALUE_PPRINT TODO:")
-    "usdlux_advanced_features.usda",
-    "usdlux_basic_lights.usda",
     # Spectral emission (wavelength:emission) not fully supported
     "spectral-emission-002.usda",
     "spectral-emission-preset-f2.usda",