[YouTube] Address review comments

Author: Stypox

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeParsingHelper.java

@@ -177,8 +177,6 @@ private YoutubeParsingHelper() {
     private static final Pattern C_WEB_PATTERN = Pattern.compile("&c=WEB");
     private static final Pattern C_WEB_EMBEDDED_PLAYER_PATTERN =
             Pattern.compile("&c=WEB_EMBEDDED_PLAYER");
-    private static final Pattern C_TVHTML5_PLAYER_PATTERN =
-            Pattern.compile("&c=TVHTML5");
     private static final Pattern C_ANDROID_PATTERN = Pattern.compile("&c=ANDROID");
     private static final Pattern C_IOS_PATTERN = Pattern.compile("&c=IOS");
 

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

@@ -998,6 +998,10 @@ private void fetchWebClientMetadataAndSetThumbnails(
             final JsonObject webPlayerResponse = YoutubeStreamHelper.getWebMetadataPlayerResponse(
                     localization, contentCountry, videoId);
 
+            // Important note: we don't checkPlayabilityStatus() here, because we use this request
+            // exclusively for metadata, not for extracting streams. It turns out that when
+            // YouTube returns a playability status error, the metadata may still be there.
+
             if (!isPlayerResponseNotValid(webPlayerResponse, videoId)) {
                 // The microformat JSON object of the content is only returned on the WEB client,
                 // so we need to store it instead of getting it directly from the playerResponse