Automatic model type detection

[dvirmor]

Description
When I create a model directory without configuration, the server try to detect the model type from the first version and not from the latest version. In this case, if my first version model is onnx type and my second version is trt type, without configuration the server will search for model.onnx instead model.plan

Triton Information
What version of Triton are you using?
23.04

Are you using the Triton container or did you build it yourself?
container

To Reproduce
Create model with 2 versions, onnx and trt. After this try to run the server.

Expected behavior
I expect that if the automatic configuration take the latest model, it needs to take the model type of the latest version and not the first version.