fix: git merge button visibility on branch change after a successful merge (#38847)

## Description
The `mergeSuccess` status in the reducer was not getting reset on branch
change.
Introduced a new action to reset it on change

Fixes https://github.com/appsmithorg/appsmith/issues/38844

## Automation

/ok-to-test tags="@tag.Git"

### 🔍 Cypress test results
<!-- This is an auto-generated comment: Cypress test results  -->
> [!TIP]
> 🟢 🟢 🟢 All cypress tests have passed! 🎉 🎉 🎉
> Workflow run:
<https://github.com/appsmithorg/appsmith/actions/runs/12983463132>
> Commit: f012fbbee3bbf48f85b8262264c3cd525791a246
> <a
href="https://internal.appsmith.com/app/cypress-dashboard/rundetails-65890b3c81d7400d08fa9ee5?branch=master&workflowId=12983463132&attempt=1"
target="_blank">Cypress dashboard</a>.
> Tags: `@tag.Git`
> Spec:
> <hr>Mon, 27 Jan 2025 07:39:33 UTC
<!-- end of auto-generated comment: Cypress test results  -->


## Communication
Should the DevRel and Marketing teams inform users about this change?
- [ ] Yes
- [ ] No


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- Enhanced merge state management with a new `resetMergeSuccessState`
function
	- Improved ability to reset merge success state during branch selection

- **Bug Fixes**
	- Resolved potential state persistence issues in merge operations

- **Refactor**
- Updated hooks and components to support more flexible merge state
handling

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

app/client/src/git/components/OpsModal/TabMerge/TabMergeView.tsx

@@ -80,6 +80,7 @@ interface TabMergeViewProps {
   mergeStatus: FetchMergeStatusResponseData | null;
   protectedBranches: FetchProtectedBranchesResponseData | null;
   resetMergeState: () => void;
+  resetMergeSuccessState: () => void;
 }
 
 export default function TabMergeView({
@@ -99,6 +100,7 @@ export default function TabMergeView({
   mergeStatus = null,
   protectedBranches = null,
   resetMergeState = noop,
+  resetMergeSuccessState = noop,
 }: TabMergeViewProps) {
   const [selectedBranchOption, setSelectedBranchOption] =
     useState<BranchOption>();
@@ -208,9 +210,15 @@ export default function TabMergeView({
       // when user selects a branch to merge
       if (currentBranch && selectedBranchOption?.value) {
         fetchMergeStatus(currentBranch, selectedBranchOption?.value);
+        resetMergeSuccessState();
       }
     },
-    [currentBranch, selectedBranchOption?.value, fetchMergeStatus],
+    [
+      currentBranch,
+      selectedBranchOption?.value,
+      fetchMergeStatus,
+      resetMergeSuccessState,
+    ],
   );
 
   useEffect(

app/client/src/git/components/OpsModal/TabMerge/index.tsx

@@ -16,6 +16,7 @@ export default function TabMerge() {
     mergeError,
     mergeStatus,
     resetMergeState,
+    resetMergeSuccessState,
   } = useMerge();
   const { isFetchStatusLoading, status } = useStatus();
   const { branches, currentBranch, fetchBranches, isFetchBranchesLoading } =
@@ -42,6 +43,7 @@ export default function TabMerge() {
       mergeStatus={mergeStatus}
       protectedBranches={protectedBranches}
       resetMergeState={resetMergeState}
+      resetMergeSuccessState={resetMergeSuccessState}
     />
   );
 }

app/client/src/git/hooks/useMerge.ts

@@ -66,6 +66,12 @@ export default function useMerge() {
     }
   }, [artifactDef, dispatch]);
 
+  const resetMergeSuccessState = useCallback(() => {
+    if (artifactDef) {
+      dispatch(gitArtifactActions.resetMergeSuccessState({ artifactDef }));
+    }
+  }, [artifactDef, dispatch]);
+
   return {
     isMergeLoading: mergeState?.loading ?? false,
     mergeError: mergeState?.error ?? null,
@@ -77,5 +83,6 @@ export default function useMerge() {
     clearMergeStatus,
     isMergeSuccess: isMergeSuccess ?? false,
     resetMergeState,
+    resetMergeSuccessState,
   };
 }

app/client/src/git/store/actions/mergeActions.ts

@@ -40,3 +40,9 @@ export const resetMergeStateAction = createArtifactAction((state) => {
 
   return state;
 });
+
+export const resetMergeSuccessAction = createArtifactAction((state) => {
+  state.ui.mergeSuccess = false;
+
+  return state;
+});

app/client/src/git/store/gitArtifactSlice.ts

@@ -85,6 +85,7 @@ import {
   mergeInitAction,
   mergeSuccessAction,
   resetMergeStateAction,
+  resetMergeSuccessAction,
 } from "./actions/mergeActions";
 import {
   pollAutocommitProgressStopAction,
@@ -192,6 +193,7 @@ export const gitArtifactSlice = createSlice({
     mergeSuccess: mergeSuccessAction,
     mergeError: mergeErrorAction,
     resetMergeState: resetMergeStateAction,
+    resetMergeSuccessState: resetMergeSuccessAction,
     pullInit: pullInitAction,
     pullSuccess: pullSuccessAction,
     pullError: pullErrorAction,