Fix initializing an implementation of an abstract base component

[rconner46]

What changed?

The SDK is unable to initialize an abstract BaseComponent with a valid, non-abstract, Implementation. Something like the following example:

@Implementation(is = ImplementationComponent.class, on = Platform.WEB)
// There could also be an implementation on other platforms
public abstract SomeComponent extends BaseComponent {
    // Some locators
    
    // Some abstract methods
}

public ImplementationComponent extends SomeComponent {
    // Implementation of the above
}

This was possible in version 5.x of the SDK. The issue is with the abstract check within the BaseComponentBuilder. It was being performed on the class being passed in to the BaseComponentBuilder instead of the implementation class that we look up from the annotation.