Allow growth of items not in grid (e.g. manually placed by designer)

[finger563]

Is your feature request related to a problem?

We can't have things like in stardew valley which are at specific spots / in specific regions and which grow / change over time easily.

Describe the solution you'd like.

Allow growth manager to register / handle items not in grids.

Describe alternatives you've considered.

Alternatively, we could have them simply be in the actor's blueprints, possibly within volumes or something for spawning?

Additional context.

No response

[finger563]

Simple enough to have growth manager support registration, then have the growable_base item register with growth manager in begin play if it is not in a grid. Would need to see if there is a race condition around item spawning.

Conversely, it might just be easier to get rid of the growth manager's interaction with the grid, and instead simply have all growables register with the growth manager. The grid could then get neighboring cells (if any) as needed.