What I did was create a Project extension function configureLint that takes in a CommonExtension (both LibraryExtension and ApplicationExtension implements CommonExtension):

internal fun Project.configureLint(commonExtension: CommonExtension<*, *, *, *, *, *>){
    with(commonExtension) {
        lint {
            abortOnError = false
            ...
        }
    }
}

Then applied to to both the AppPlugin and LibraryPlugin that I've defined using ApplicationExtension and LibraryExtension respectively:

class AppPlugin : Plugin<Project> {
    override fun apply(target: Project) {
        with(target) {
            extensions.configure<ApplicationExtension> {
                configureLint(this)
            }
        }
    }
}

class LibraryPlugin : Plugin<Project> {
    override fun apply(target: Project) {
        with(target) {
            extensions.configure<LibraryExtension> {
                configureLint(this)
            }
        }
    }
}