Material Canvas: Hide the generated *.azsli files

[Andre-LA]

Is your feature request related to a problem? Please describe.
After the processing of a material graph, the generated azsli files are exposed in the same directory of the graph and the generated material, making the asset browsing more confusing.

Describe the solution you'd like
Add an option that controls if the developer wants these files exposed to the user (for editing) or hidden (like the generated Lua files of the Script Canvas), where the hidden option would be the default.

Additional context