Remove redundant Redmi 8 on-disk RAW test assumptions

DngCreatorSizeMismatchQuirk filters out non-sensor-sized RAW
resolutions on Redmi 8 (olive) and Redmi 8A (olivelite), ensuring
CameraX configures sensor-matching resolutions so that DngCreator
can write on-disk DNGs without throwing size mismatch exceptions.

This CL removes the obsolete assumeFalse(olive) in
ImageCaptureRawFormatTest on-disk test methods.

Bug: 544524419
Test: ImageCaptureRawFormatTest on olive and olivelite
Change-Id: Icc5b57699606e28e924904156f141d72abd32356