Model properties mapped with _self cause unnecessary link resolver round trip

[willprice76]

In the GenericSemanticModelDataConverter.selfLink method there is always a round trip to the link resolver to resolve the link:
https://github.com/sdl/dxa-web-application-java/blob/58a4fdebafc192b9a87570c684bd97d9091fdc5f/dxa-framework/dxa-tridion-provider/src/main/java/com/sdl/dxa/tridion/mapping/converter/GenericSemanticModelDataConverter.java#L83
This can be unnecessary as:

1. If you want to convert to an EntityModel, you don't use the link URL
2. Using the DXA 2.0 model service there should already be a resolved link URL in the EntityModelData (check .getLinkUrl())

This will cause performance problems on pages containing many component presentations, which map to models with a _self SemanticProperty annotation.