DCL.Diagnostics.EcsSystemException: [MainCameraSystem]

Sentry Issue: [UNITY-EXPLORER-Q04](https://decentraland.sentry.io/issues/7715252408/)

```
System.NullReferenceException: Object reference not set to an instance of an object.
File "DCL.Plugins__15.cpp", line 14926, in HandleActiveVirtualCameraLookAtChange
File "il2cpp-codegen-oldintrinsics.h", line 140, in HandleActiveVirtualCameraLookAtChangeQuery
File "il2cpp-codegen-oldintrinsics.h", line 146, in HandleActiveVirtualCameraLookAtChangeQuery
File "DCL.Plugins__15.cpp", line 31949, in HandleActiveVirtualCameraLookAtChangeQuery
File "DCL.Plugins__15.cpp", line 14482, in Update
...
(14 additional frame(s) were not displayed)

DCL.Diagnostics.EcsSystemException: [MainCameraSystem]
File "ECS.Core.cpp", line 7508, in Update
File "il2cpp-codegen.h", line 792, in Update
File "Generics__20.cpp", line 22174, in Update
File "Generics__17.cpp", line 31921, in UpdateInternal
File "ECS.Core.cpp", line 3355, in Update
...
(8 additional frame(s) were not displayed)

System.NullReferenceException: Object reference not set to an instance of an object.
File "DCL.Plugins__15.cpp", line 14926, in HandleActiveVirtualCameraLookAtChange
File "il2cpp-codegen-oldintrinsics.h", line 140, in HandleActiveVirtualCameraLookAtChangeQuery
File "il2cpp-codegen-oldintrinsics.h", line 146, in HandleActiveVirtualCameraLookAtChangeQuery
File "DCL.Plugins__15.cpp", line 31949, in HandleActiveVirtualCameraLookAtChangeQuery
File "DCL.Plugins__15.cpp", line 14482, in Update
...
(14 additional frame(s) were not displayed)

DCL.Diagnostics.EcsSystemException: [MainCameraSystem]
File "ECS.Core.cpp", line 7508, in Update
File "il2cpp-codegen.h", line 792, in Update
File "Generics__20.cpp", line 22174, in Update
File "Generics__17.cpp", line 31921, in UpdateInternal
File "ECS.Core.cpp", line 3355, in Update
...
(8 additional frame(s) were not displayed)

System.NullReferenceException: Object reference not set to an instance of an object.
File "DCL.Plugins__15.cpp", line 14926, in HandleActiveVirtualCameraLookAtChange
File "il2cpp-codegen-oldintrinsics.h", line 140, in HandleActiveVirtualCameraLookAtChangeQuery
File "il2cpp-codegen-oldintrinsics.h", line 146, in HandleActiveVirtualCameraLookAtChangeQuery
File "DCL.Plugins__15.cpp", line 31949, in HandleActiveVirtualCameraLookAtChangeQuery
File "DCL.Plugins__15.cpp", line 14482, in Update
...
(14 additional frame(s) were not displayed)

DCL.Diagnostics.EcsSystemException: [MainCameraSystem]
File "ECS.Core.cpp", line 7508, in Update
File "il2cpp-codegen.h", line 792, in Update
File "Generics__20.cpp", line 22174, in Update
File "Generics__17.cpp", line 31921, in UpdateInternal
File "ECS.Core.cpp", line 3355, in Update
...
(8 additional frame(s) were not displayed)

System.NullReferenceException: Object reference not set to an instance of an object.
File "DCL.Plugins__15.cpp", line 14926, in HandleActiveVirtualCameraLookAtChange
File "il2cpp-codegen-oldintrinsics.h", line 140, in HandleActiveVirtualCameraLookAtChangeQuery
File "il2cpp-codegen-oldintrinsics.h", line 146, in HandleActiveVirtualCameraLookAtChangeQuery
File "DCL.Plugins__15.cpp", line 31949, in HandleActiveVirtualCameraLookAtChangeQuery
File "DCL.Plugins__15.cpp", line 14482, in Update
...
(14 additional frame(s) were not displayed)

DCL.Diagnostics.EcsSystemException: [MainCameraSystem]
File "ECS.Core.cpp", line 7508, in Update
File "il2cpp-codegen.h", line 792, in Update
File "Generics__20.cpp", line 22174, in Update
File "Generics__17.cpp", line 31921, in UpdateInternal
File "ECS.Core.cpp", line 3355, in Update
...
(8 additional frame(s) were not displayed)

SceneRunner.Scene.ExceptionsHandling.SceneExecutionException: One or more errors occurred.
```
This issue was automatically created by Sentry via [Explorer Alpha Github Issue Creation](https://sentry.io/organizations/decentraland/monitors/alerts/3130340/)

Start with the linked Sentry report, then trace HandleActiveVirtualCameraLookAtChange in DCL.Plugins__15.cpp and its callers through MainCameraSystem.Update. Reproduce or identify the null reference and verify that MainCameraSystem no longer reports this exception during scene execution.

Written by the indexing model from the issue text.