fix: Ensure cached data is up to date when models are mutated

[Eideren]

PR Details

Running the following

model.Meshes.Add(new CubeProceduralModel().Generate(game.Services).Meshes[0]);

throws when a ModelComponent was already in the scene in the preceding frame.
Fixes other similar errors, like when swapping one of the mesh, or one of the meshes' draw.

Also refactored around one of the failing method a bit to improve readability, splitting the logic into two explicit sections by flattening the inner scopes.

Related Issue

None.

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My change requires a change to the documentation.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have built and run the editor to try this change out.