Fetch again the desktop player JSON only if the content is protected by signatureCiphers

Author: AudricV

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamExtractor.java

@@ -832,7 +832,7 @@ private void fetchAndroidMobileJsonPlayer(final ContentCountry contentCountry,
             // The cipher signatures from the player endpoint without a timestamp are invalid so
             // download it again only if we didn't have a signatureTimestamp before fetching the
             // data of this video (the sts string).
-            if (!stsKnown) {
+            if (!stsKnown && isCipherProtectedContent()) {
                 sts = getStsFromPlayerJs();
                 final JsonObject playerResponseWithSignatureTimestamp = getJsonPostResponse(
                         "player", createPlayerBodyWithSts(localization, contentCountry, videoId),