Fix: Circular dependency issue with sibling schemas/definitions.

[timotheeguerin]

fix Azure/autorest#3630

When a model is following the pattern $ref and Sibling Elements described here https://swagger.io/docs/specification/using-ref/

This is causing a circular dependency issue because the model(with the properties) gets removed and the model with the reference get the ref updated to itself.

The solution is to figure out which of the 2 models to delete(The one not being a ref)

Todo:

• Tests
• Changelog

[azure-pipelines]

You may test this build by running autorest --reset and then either:

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add --use: to the command line:

autorest --use:https://tinyurl.com/ycqc8ulb ...

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or use the following in your autorest configuration:

use-extension:
  "@autorest/modelerfour": "https://tinyurl.com/ycqc8ulb" 

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If this build is good for you, give this comment a thumbs up. (👍)

And you should run autorest --reset again once you're finished testing to remove it.