This CL changes PlayerActivity's VIEW_LIST action intent contract:
Each media item configuration is provided by indexing the entries.
For example, the URI of the first item is passed as "uri_0", the
second one is "uri_1", etc. Optionally, the extra parameters, like
the extensions, are passed as "extension_1", where the intent extras
with matching indices, refer to the same media sample.
The VIEW action's contract remains unchanged.
PiperOrigin-RevId: 260518118
