Invalid $ref in aggregated JSON schemas should be removed

[fstaudt]

Invalid or unknown $ref in aggregated JSON schemas cause failure in Gradle task validateHelmValues:

java.lang.reflect.InvocationTargetException
	at jdk.internal.reflect.GeneratedConstructorAccessor81.newInstance(Unknown Source)
        ...
Caused by: com.networknt.schema.JsonSchemaException: ... is an invalid segment for URI {2}
	at com.networknt.schema.JsonSchema.combineCurrentUriWithIds(JsonSchema.java:111)
        ...

java.lang.reflect.InvocationTargetException
	at jdk.internal.reflect.GeneratedConstructorAccessor81.newInstance(Unknown Source)
        ...
Caused by: com.networknt.schema.JsonSchemaException: #/properties/global/allOf/0/$ref: Reference #/$defs/downloads/repository/json-schemas/apps/test/1.0.0/values.schema.json/properties/global cannot be resolved
	at com.networknt.schema.RefValidator.<init>(RefValidator.java:45)
        ... 138 more
	
java.lang.reflect.InvocationTargetException
	at jdk.internal.reflect.GeneratedConstructorAccessor81.newInstance(Unknown Source)
        ...
Caused by: com.networknt.schema.JsonSchemaException: #/properties/global/allOf/1/$ref: Reference #/$defs/downloads/repository/json-schemas/apps/test/1.0.0/global-values.schema.json cannot be resolved
	at com.networknt.schema.RefValidator.<init>(RefValidator.java:45)
        ... 138 more

Since those schemas are already ignored by IntelliJ IDEA, they should be removed from aggregated JSON schema.