This code is Widevine specific. `OfflineLicenseHelper.downloadLicense`
requires the passed `Format` to have a `DrmInitData.SchemeData` with
Widevine UUID and non-null `data` field. The demo app tries to check
this in advance (to avoid an exception later), but its checks are
looser than those made by `OfflineLicenseHelper`. This change tightens
the checks to match.
Issue: androidx/media#512
PiperOrigin-RevId: 549587506
(cherry picked from commit b7988e2c856ca05e28d862c8a7c7739402d4d40d)
