Very poor VP2 performances with point instancers and "Depth Peeling" or "Alpha Cut"

**Describe the bug**

We notice huge VP2 performance loss on scenes containing large point instancers when switching to `Depth Peeling` or `Alpha Cut` transparency.

The issue does not appear when world consolidation is enabled, but we need to disable it in some cases.

**Steps to reproduce**

1. Create a mayaUsd proxyShape with 100K point instances.

```python
import random
import pxr.UsdGeom
import maya.cmds
import mayaUsd.ufe
import mayaUsd_createStageWithNewLayer
maya.cmds.loadPlugin("mayaUsdPlugin", quiet=True)

proxyShape = mayaUsd_createStageWithNewLayer.createStageWithNewLayer()
shapeStage = mayaUsd.ufe.getStage(proxyShape)
shapeStage.GetRootLayer().ImportFromString('''#sdf 1
(
defaultPrim="PI"
)
def PointInstancer "PI"
{
rel prototypes = []
def Scope "Protos"
{
def Sphere "Sphere" {}
}
}
''')

instancer = pxr.UsdGeom.PointInstancer(shapeStage.GetDefaultPrim())
instCount = 100000
instBounds = (-1000.0, 1000.0)
instancer.CreateProtoIndicesAttr().Set([0] * instCount)
instancer.CreatePositionsAttr().Set([
(random.uniform(*instBounds), 0.0, random.uniform(*instBounds))
for i in range(instCount)
])
```

2. Disable VP2 consolidation. I beleive it is hiding the issue.

```python
maya.cmds.setAttr("hardwareRenderingGlobals.consolidateWorld", 0)
```

3. Draw the scene with default `Object Sorting` transparency.
```python
maya.cmds.setAttr("hardwareRenderingGlobals.transparencyAlgorithm", 1)
maya.cmds.ogs(traceRenderPipeline=True)
maya.cmds.refresh()
maya.cmds.ogs(traceRenderPipeline=False)
# -- VP2 Trace[modelPanel4][3d Beauty Pass]
# Count for list: [Opaque] = 1
```

4. Check VP2 performances:
- traceRenderPipeline shows a unique (instanced) opaque item.
- maya profiler shows
- `VP2UpdateScene` ≈ 300us
- `VP2Draw3dBeautyPass` ≈ 400us
- `VP2ClearRenderLists` ≈ 2us

5. Draw the scene with `Depth Peeling` transparency (or `ALpha Cut`)
```python
maya.cmds.setAttr("hardwareRenderingGlobals.transparencyAlgorithm", 3)
maya.cmds.ogs(traceRenderPipeline=True)
maya.cmds.refresh()
maya.cmds.ogs(traceRenderPipeline=False)
# -- VP2 Trace[modelPanel4][3d Beauty Pass]
# Count for list: [Opaque] = 100000
# Count for list: [Opaque] = 100000
```

6. Check VP2 performances:
- traceRenderPipeline shows 100000 (non-instanced) opaque items.
- maya profiler shows
- `VP2UpdateScene` ≈ 120ms
- `VP2Draw3dBeautyPass` ≈ 500ms
- `VP2ClearRenderLists` ≈ 40ms

**Specs (if applicable):**

- CentOS 7.8
- Maya 2023.3
- maya-usd 0.25
- USD 22.11