fix(explore): close unsaved changes modal when discarding changes (#35307)

(cherry picked from commit d8688cf)

Author: rebenitez1802

superset-frontend/src/hooks/useUnsavedChangesPrompt/index.ts

@@ -41,6 +41,7 @@ export const useUnsavedChangesPrompt = ({
   const manualSaveRef = useRef(false); // Track if save was user-initiated (not via navigation)
 
   const handleConfirmNavigation = useCallback(() => {
+    setShowModal(false);
     confirmNavigationRef.current?.();
   }, []);
 

superset-frontend/src/hooks/useUnsavedChangesPrompt/useUnsavedChangesPrompt.test.tsx

@@ -103,4 +103,33 @@ describe('useUnsavedChangesPrompt', () => {
     expect(onSave).toHaveBeenCalled();
     expect(result.current.showModal).toBe(false);
   });
+
+  it('should close modal when handleConfirmNavigation is called', () => {
+    const onSave = jest.fn();
+
+    const { result } = renderHook(
+      () =>
+        useUnsavedChangesPrompt({
+          hasUnsavedChanges: true,
+          onSave,
+        }),
+      { wrapper },
+    );
+
+    // First, trigger navigation to show the modal
+    act(() => {
+      const unblock = history.block((tx: any) => tx);
+      unblock();
+      history.push('/another-page');
+    });
+
+    expect(result.current.showModal).toBe(true);
+
+    // Then call handleConfirmNavigation to discard changes
+    act(() => {
+      result.current.handleConfirmNavigation();
+    });
+
+    expect(result.current.showModal).toBe(false);
+  });
 });