Checks if the specified model is valid.
A model is considered invalid in following cases:
- Starts with a space or maps
- Doesn't start with models
- Contains any of the following:
- On server: If the model isn't precached, if the model file doesn't exist on the disk
- If precache failed
- Model is the error model
1 string modelName
Name/Path of the model to check.
Whether the model is valid or not. Returns false clientside if the model is not precached by the server.