removed unused function (HIDL_FETCH_ISurfaceFlingerConfigs)

HIDL_FETCH_... is required only for passthrough mode, but Configstore
does not provide passthrough mode.

Bug: 35325577
Test: build and check configstore works

Change-Id: I35e916ad4a6c321303a3888dabb4884b17146e16
Merged-In: Iac3ed57568f18c3a8a7f7423a361b0fe45aa54ab