feat: Change the default priority mechanism to be based on gas price …

…(backport cosmos#12953) (cosmos#13006)

* feat: Change the default priority mechanism to be based on gas price (cosmos#12953)

(cherry picked from commit befd816)

# Conflicts:
#	CHANGELOG.md
#	x/auth/ante/fee_test.go

* fix conflict

Co-authored-by: yihuang <huang@crypto.com>
Co-authored-by: Julien Robert <julien@rbrt.fr>

CHANGELOG.md

@@ -40,6 +40,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* [#12953](https://github.com/cosmos/cosmos-sdk/pull/12953) Change the default priority mechanism to be based on gas price.
 * [#12981](https://github.com/cosmos/cosmos-sdk/pull/12981) Return proper error when parsing telemetry configuration.
 * [#12969](https://github.com/cosmos/cosmos-sdk/pull/12969) Bump Tendermint to `v0.34.21` and IAVL to `v0.19.1`.
 * [#12886](https://github.com/cosmos/cosmos-sdk/pull/12886) Amortize cost of processing cache KV store.

x/auth/ante/fee_test.go

@@ -66,7 +66,7 @@ func (s *AnteTestSuite) TestEnsureMempoolFees() {
 	// msg and signatures
 	msg := testdata.NewTestMsg(accs[0].acc.GetAddress())
 	feeAmount := testdata.NewTestFeeAmount()
-	gasLimit := testdata.NewTestGasLimit()
+	gasLimit := uint64(15)
 	s.Require().NoError(s.txBuilder.SetMsgs(msg))
 	s.txBuilder.SetFeeAmount(feeAmount)
 	s.txBuilder.SetGasLimit(gasLimit)
@@ -76,7 +76,7 @@ func (s *AnteTestSuite) TestEnsureMempoolFees() {
 	s.Require().NoError(err)
 
 	// Set high gas price so standard test fee fails
-	atomPrice := sdk.NewDecCoinFromDec("atom", math.LegacyNewDec(20))
+	atomPrice := sdk.NewDecCoinFromDec("atom", sdk.NewDec(20))
 	highGasPrice := []sdk.DecCoin{atomPrice}
 	s.ctx = s.ctx.WithMinGasPrices(highGasPrice)
 
@@ -108,9 +108,9 @@ func (s *AnteTestSuite) TestEnsureMempoolFees() {
 
 	newCtx, err := antehandler(s.ctx, tx, false)
 	s.Require().Nil(err, "Decorator should not have errored on fee higher than local gasPrice")
-	// Priority is the smallest amount in any denom. Since we have only 1 fee
-	// of 150atom, the priority here is 150.
-	s.Require().Equal(feeAmount.AmountOf("atom").Int64(), newCtx.Priority())
+	// Priority is the smallest gas price amount in any denom. Since we have only 1 gas price
+	// of 10atom, the priority here is 10.
+	s.Require().Equal(int64(10), newCtx.Priority())
 }
 
 func (s *AnteTestSuite) TestDeductFees() {