I’m not sure about what is your question… The class exists in the .jar, but your IssuesLoaderSensor class is instantiated by SonarQube Scanner and it’s responsible for creating instances of Configuration, FileSystem and RulesProfile classes (to call the class constructor).
In SonarQube 7.6, the SonarQube Scanner engine stopped providing instances of RulesProfile. Therefore, it won’t create instances of RulesProfile anymore.
You must change your code to use org.sonar.api.batch.rule.ActiveRules.