Remove confusing @throws clauses from MediaLibrarySessionCallback

These seem to be describing an exception being thrown based on a
property of the value being returned from this method? Or is the
expectation that every implementation of this interface throws the
AssertionError themselves.

Given AssertionError is unchecked, and shouldn't be explicitly caught
anywhere, it seems easiest just to remove all this documentation?

PiperOrigin-RevId: 406107606

libraries/session/src/main/java/androidx/media3/session/MediaLibraryService.java

@@ -157,8 +157,6 @@ public abstract class MediaLibraryService extends MediaSessionService {
        * @param browser The browser information.
        * @param params The optional parameters passed by the browser.
        * @return A pending result that will be resolved with a root media item.
-       * @throws AssertionError if {@link LibraryResult#value} is {@code null} while {@link
-       *     LibraryResult#resultCode} is {@link LibraryResult#RESULT_SUCCESS}.
        * @see SessionCommand#COMMAND_CODE_LIBRARY_GET_LIBRARY_ROOT
        */
       default ListenableFuture<LibraryResult<MediaItem>> onGetLibraryRoot(
@@ -211,9 +209,6 @@ public abstract class MediaLibraryService extends MediaSessionService {
        * @param pageSize The page size to get the paginated result. Will be greater than {@code 0}.
        * @param params The optional parameters passed by the browser.
        * @return A pending result that will be resolved with a list of media items.
-       * @throws AssertionError if {@link LibraryResult#value} is {@code null} or has size greater
-       *     than the {@code pageSize} while {@link LibraryResult#resultCode} is {@link
-       *     LibraryResult#RESULT_SUCCESS}.
        * @see SessionCommand#COMMAND_CODE_LIBRARY_GET_CHILDREN
        */
       default ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetChildren(
@@ -341,9 +336,6 @@ public abstract class MediaLibraryService extends MediaSessionService {
        * @param pageSize The page size to get the paginated result. Will be greater than {@code 0}.
        * @param params The optional parameters passed by the browser.
        * @return A pending result that will be resolved with a list of media items.
-       * @throws AssertionError if {@link LibraryResult#value} is {@code null} or has size greater
-       *     than the {@code pageSize} while {@link LibraryResult#resultCode} is {@link
-       *     LibraryResult#RESULT_SUCCESS}.
        * @see SessionCommand#COMMAND_CODE_LIBRARY_GET_SEARCH_RESULT
        */
       default ListenableFuture<LibraryResult<ImmutableList<MediaItem>>> onGetSearchResult(