Changes to Gerber Covariance Matrix

removed the request property oneOf[subschema #2]/assets/items/assetPrices/items/high

removed the request property oneOf[subschema #2]/assets/items/assetPrices/items/low

removed the request property oneOf[subschema #2]/assets/items/assetPrices/items/open

the request's body type changed from object to no type

removed the request property assets

removed the request property gerberThreshold

added subschema #1 subschema #2 to the request body oneOf list