fix: Reset text visibility on unload (#8775)

Author: avelad

lib/player.js

@@ -1575,6 +1575,7 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
         await this.textDisplayer_.destroy();
         this.textDisplayer_ = null;
       }
+      this.isTextVisible_ = false;
 
       if (this.video_) {
         // The life cycle of tracks that created by addTextTrackAsync() and

test/player_unit.js

@@ -2809,6 +2809,7 @@ describe('Player', () => {
 
     it('chooses the configured text language and role at start', async () => {
       player.configure({
+        autoShowText: shaka.config.AutoShowText.IF_PREFERRED_TEXT_LANGUAGE,
         preferredTextLanguage: 'en',
         preferredTextRole: 'commentary',
       });