I read the documentation and fixed my problem with this solution. Thanks to @brendo234!

val headers = mutableMapOf<String, String>()
    val bundleId = //your package name // Sample: "com.sampleapp
    val referrer = "https://$bundleId"
    headers.put("Referer",referrer)
    binding.webview.loadUrl("https://www.youtube.com/embed/$videoId",headers)