fix: honor autoShowText on non-audio streams (#6977)

lib/player.js

@@ -6940,7 +6940,7 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
     // Check if we should show text (based on difference between audio and text
     // languages).
     if (initialTextStream) {
-      if (initialVariant.audio && this.shouldInitiallyShowText_(
+      if (this.shouldInitiallyShowText_(
           initialVariant.audio, initialTextStream)) {
         this.isTextVisible_ = true;
       }
@@ -6960,7 +6960,7 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
   /**
    * Check if we should show text on screen automatically.
    *
-   * @param {shaka.extern.Stream} audioStream
+   * @param {?shaka.extern.Stream} audioStream
    * @param {shaka.extern.Stream} textStream
    * @return {boolean}
    * @private
@@ -6991,6 +6991,9 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
     }
 
     if (this.config_.autoShowText == AutoShowText.IF_SUBTITLES_MAY_BE_NEEDED) {
+      if (!audioStream) {
+        return false;
+      }
       /* The text should automatically be shown if the text is
        * language-compatible with the user's text language preference, but not
        * compatible with the audio.  These are cases where we deduce that