Cleanup the MediaItem.Builder javadoc for 'conditional' setters

Many of the setters are ignored unless others are set - this change:
* Lists these conditions exhaustively.
* Uses more concise language to avoid overshadowing the main details
  of what the setter sets.
* Tweaks the language from 'is ignored' to 'shouldn't be called', to
  open up the future possibility of throwing an error if these are
  called without the 'required' setter also being present (see
  Issue: #8957).

#minor-release

PiperOrigin-RevId: 376162385

RELEASENOTES.md

@@ -6,6 +6,8 @@
     *   Fix gradle config to allow specifying a relative path for
     *   Fix gradle config to allow specifying a relative path for
         `exoplayerRoot` when [depending on ExoPlayer locally](README.md#locally)
         `exoplayerRoot` when [depending on ExoPlayer locally](README.md#locally)
         ([#8927](https://github.com/google/ExoPlayer/issues/8927)).
         ([#8927](https://github.com/google/ExoPlayer/issues/8927)).
+    *   Update `MediaItem.Builder` javadoc to discourage calling setters that
+        will be (currently) ignored if another setter is not also called.
 *   Extractors:
 *   Extractors:
     *   Add support for MPEG-H 3D Audio in MP4 extractors
     *   Add support for MPEG-H 3D Audio in MP4 extractors
         ([#8860](https://github.com/google/ExoPlayer/pull/8860)).
         ([#8860](https://github.com/google/ExoPlayer/pull/8860)).