Fix NullPointerException in YouTubeStreamExtractor.getStreamSegments() (#797)

Fix NullPointerException in YouTubeStreamExtractor.getStreamSegments()

Co-authored-by: litetex <40789489+litetex@users.noreply.github.com>

Author: TobiGr

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

@@ -1272,8 +1272,7 @@ public List<StreamSegment> getStreamSegments() throws ParsingException {
                 final String panelIdentifier = panels.getObject(i)
                         .getObject("engagementPanelSectionListRenderer")
                         .getString("panelIdentifier");
-                if (panelIdentifier.equals(
-                        "engagement-panel-macro-markers-description-chapters")) {
+                if ("engagement-panel-macro-markers-description-chapters".equals(panelIdentifier)) {
                     segmentsArray = panels.getObject(i)
                             .getObject("engagementPanelSectionListRenderer").getObject("content")
                             .getObject("macroMarkersListRenderer").getArray("contents");