Fix grid world template crashing

[Nytra]

https://discord.com/channels/901126079857692714/1365170008165978117

Please test code in the future (I know this is partially on me because I approved the PR)

Unhandled Exception when updating world: . State Running, Refresh Stage: RefreshBegin, Init State: Finished, SyncTick 1, StateVersion: 2
System.Exception: Target and source types must match! Source: Elements.Core.float2, Target: Elements.Core.float3
   at void FrooxEngine.ValueCopyExtensions.DriveFrom(IField field, IField source, bool writeBack, bool keepOriginalValue, bool searchForDuplicate)
   at bool CommunityBugFixCollection.BetterGridWorldPreset.Prefix(World w)
   at bool FrooxEngine.World.RefreshStep()
   at bool FrooxEngine.World.Refresh()
   at void FrooxEngine.WorldManager.UpdateStep()

[Banane9]

When you just want to add a little tweak and think it's fine because it compiles still 😩