Conflicting Success and Error Messages When Updating Bank Details on Bank Management Page

Describe the bug
On the Bank Management page, when a user updates their bank information, two messages are shown:

An error message indicating the update was unsuccessful.
A success message indicating the bank details were updated successfully.
This creates confusion about whether the update actually went through.

To Reproduce
Steps to reproduce the behavior:

Open the Bank Management page in the app.
Edit and update the bank account information.
Tap the Update button.
Observe that both a success and an error message are displayed simultaneously or in quick succession.
Expected behavior
Only one appropriate message should appear based on the actual outcome. If the update is successful, only the success message should display. If it fails, only the error message should be shown.
Smartphone (please complete the following information):

Device: Samsung A15

Additional context
This may be due to duplicate response handling in the frontend logic or inconsistent API feedback. It should be resolved to prevent confusion and ensure clear user communication.

Start at the Bank Management page and trace the frontend update flow from the Update button through its success and error response handling. Reproduce the issue with bank account information, then verify that a successful update shows only the success message and a failed update shows only the error message.

Written by the indexing model from the issue text.