`indra-licenser-spotless` doesn't work with Ktlint

[phinner]

For some reason, when you use the spotless plugin alongside Indra and that you use Ktlint for formatting, the license header is not applied in the source files. Here is a test build.gradle.kts to reproduce this issue.

plugins {
    kotlin("jvm") version "1.8.21"
    id("com.diffplug.spotless") version "6.19.0"
    id("net.kyori.indra.licenser.spotless") version "3.1.1"
}

group = "org.example"
version = "1.0-SNAPSHOT"

repositories {
    mavenCentral()
}

dependencies {
    implementation(kotlin("stdlib"))
}

spotless {
    kotlin {
        ktlint()
    }
    kotlinGradle {
        ktlint()
    }
}

indraSpotlessLicenser {
    licenseHeaderFile(rootProject.file("HEADER.md"))
}

kotlin {
    jvmToolchain(17)
}

[zml2008]

This happens with spotless's license header step and ktlint upstream too, please report to them.