Proposal validation messages should reset after success

[elsehow]

After a failed vote (e.g., insufficient fees), the UI displays an error message. If the user re-submits the transaction and it succeeds, the error message persists. It should disappear.

Steps to reproduce.

• Vote on a proposal, providing insufficient fees.
• Confirm that an error message appears under the vote buttons.
• Vote again, this time providing sufficient fees.
• Confirm that the vote succeeds.

Observed behavior: Original error message persists.

Expected behavior: Error message should disappear after successful vote.