fix: remove duplicate ante events (backport #13983) (#14142)

* fix: remove duplicate ante events (#13983)

## Description

After enabling the post-handler on our chain, we realised something odd with our transaction events. The ordering was `[ANTE, MSGS, ANTE, POST]`. After doing some digging, we realised that the context used inside the post-handler still contains the events from the ante-handler.

This should be backported to v0.46.x and v0.47.x 😄
Happy to make it compatible with #13940 when that gets merged!

cc @mbreithecker

---

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(cherry picked from commit 25449b5)

# Conflicts:
#	CHANGELOG.md

* fix changelog

Co-authored-by: John Letey <[email protected]>
Co-authored-by: Julien Robert <[email protected]>

CHANGELOG.md

@@ -48,6 +48,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Bug Fixes
 
+* (baseapp) [#13983](https://github.com/cosmos/cosmos-sdk/pull/13983) Don't emit duplicate ante-handler events when a post-handler is defined.
 * (baseapp) [#14049](https://github.com/cosmos/cosmos-sdk/pull/14049) Fix state sync when interval is zero.
 
 ## [v0.46.6](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.46.6) - 2022-11-18

baseapp/baseapp.go

@@ -721,7 +721,12 @@ func (app *BaseApp) runTx(mode runTxMode, txBytes []byte) (gInfo sdk.GasInfo, re
 		//
 		// Note: If the postHandler fails, we also revert the runMsgs state.
 		if app.postHandler != nil {
-			newCtx, err := app.postHandler(runMsgCtx, tx, mode == runTxModeSimulate)
+			// The runMsgCtx context currently contains events emitted by the ante handler.
+			// We clear this to correctly order events without duplicates.
+			// Note that the state is still preserved.
+			postCtx := runMsgCtx.WithEventManager(sdk.NewEventManager())
+
+			newCtx, err := app.postHandler(postCtx, tx, mode == runTxModeSimulate)
 			if err != nil {
 				return gInfo, nil, nil, priority, err
 			}