[YouTube] Clarify BotGuard API key's origin and disable related Sonar warning

Author: AudricV

app/src/main/java/org/schabi/newpipe/util/potoken/PoTokenWebView.kt

@@ -324,7 +324,8 @@ class PoTokenWebView private constructor(
 
     companion object : PoTokenGenerator.Factory {
         private val TAG = PoTokenWebView::class.simpleName
-        private const val GOOGLE_API_KEY = "AIzaSyDyT5W0Jh49F30Pqqtyfdf7pDLFKLJoAnw"
+        // Public API key used by BotGuard, which has been got by looking at BotGuard requests
+        private const val GOOGLE_API_KEY = "AIzaSyDyT5W0Jh49F30Pqqtyfdf7pDLFKLJoAnw" // NOSONAR
         private const val REQUEST_KEY = "O43z0dpjhgX20SCx4KAo"
         private const val USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) " +
             "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.3"