Certora - fixing failing job due to flag deprecation (#827)

Co-authored-by: Michael M <[email protected]>

Author: miguelmtzinf

certora/scripts/verifyAToken.sh

@@ -2,7 +2,6 @@ certoraRun certora/harness/SimpleERC20.sol \
             certora/harness/ATokenHarness.sol \
     --verify ATokenHarness:certora/specs/AToken.spec \
     --link ATokenHarness:_underlyingAsset=SimpleERC20 \
-    --settings -enableGhostGrounding=true \
     --optimistic_loop \
     --solc solc8.10 \
     --cloud master \