Camera: Set buffer request stream id

Additionally fix a possible issue with the buffer request index
and variable shadowing.

Bug: 129090247
Test: adb shell
/data/nativetest64/VtsHalCameraProviderV2_4TargetTest/VtsHalCameraProviderV2_4TargetTest
--hal_service_instance=android.hardware.camera.provider@2.4::ICameraProvider/legacy/0

Change-Id: I34ab0285e59233c1b6d276f9167372ef3b0bbd0b