Cached reflection captures on primitives are not cleared properly when a reflection capture proxy is released.

The issue is a race condition that only reproduces under the following conditions within a frame:

1. A reflection capture proxy is released.
2. A separate primitive referencing the proxy as a cached reflection component is added to the scene (e.g. due to a SetTransform call). This must happen between when the proxy is released and the next InitViews call on the render thread.

This results in a crash on the mobile base pass mesh processor, which attempts to dereference the cached reflection proxy. AddToScene will attempt to cache the reflection proxy, but only if it is null. Thus, cached proxies must be nulled out after a removal event to avoid this scenario.