SDK / exoplayer

Notes:
- The only functional change is that createForRemote now assings ERROR_CODE_REMOTE_ERROR.
- createForSource still uses ERROR_CODE_UNSPECIFIED, even though it expects an
  IOException. The reason for not using ERROR_CODE_IO_UNSPECIFIED is that the reason for
  the error might not be IO. For example, malformed media, or BehindLiveWindowException,
  which have non-IO error codes. So using UNSPECIFIED saves a later change in category.
PiperOrigin-RevId: 374390407