Opp: Remove unused Constants.EXTRA_SHOW_ALL_FILES

There is no place that uses EXTRA_SHOW_ALL_FILES.
This CL removes it and all the related code.

Bug: 318610752
Test: atest BluetoothOppTransferHistoryTest
Test: m -j;
Flag: EXEMPT, dead code removal
Change-Id: I7cc45bce7bb2c0e2bcbc5ea950fdff8e546e45d9