SDK / exoplayer

Based on
https://developer.android.com/reference/android/media/MediaCodec#using-an-output-surface,
frame dropping behaviour depends on the target SDK version.
After this change transformer will only use
MediaFormat#KEY_ALLOW_FRAME_DROP if both the target and system SDK
version are at least 29 and default to its pre 29 behaviour where each
decoder output frame must be processed before a new one is rendered
to prevent frame dropping otherwise.

Also remove deprecated Transformer.Builder constructor without a
context and the context setter.

PiperOrigin-RevId: 453971097
(cherry picked from commit a105d033)