Remove unsed import from RecommendedStreamConfigurationMap

The string symbol

  com.android.internal.R.string.hardware

is resolved as

  "Use on-screen keyboard",

which has nothing to do with camera.

Before removing the above string symbol, let's clean up this unused
reference.

Bug: 304460009
Test: presubmit
Change-Id: I22a5820b9abaff45c7e5d7c3408359097449a34d