fix: restore original ERROR_EMPTY_MESSAGE_TEXT wording

Keeps the default error string identical to the pre-PR version so
standalone sendFeedback consumers matching on the exact message
string see no behavior change.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: logaretm

packages/feedback/src/constants/index.ts

@@ -26,7 +26,7 @@ export const HIGHLIGHT_TOOL_TEXT = 'Highlight';
 export const HIDE_TOOL_TEXT = 'Hide';
 export const REMOVE_HIGHLIGHT_TEXT = 'Remove';
 
-export const ERROR_EMPTY_MESSAGE_TEXT = 'Unable to submit feedback with an empty message';
+export const ERROR_EMPTY_MESSAGE_TEXT = 'Unable to submit feedback with empty message';
 export const ERROR_NO_CLIENT_TEXT = 'No client setup, cannot send feedback.';
 export const ERROR_TIMEOUT_TEXT = 'Unable to determine if Feedback was correctly sent.';
 export const ERROR_FORBIDDEN_TEXT =

packages/feedback/test/core/sendFeedback.test.ts

@@ -269,7 +269,7 @@ describe('sendFeedback', () => {
 
   it('throws when message is empty', () => {
     mockSdk();
-    expect(() => sendFeedback({ message: '' })).toThrow('Unable to submit feedback with an empty message');
+    expect(() => sendFeedback({ message: '' })).toThrow('Unable to submit feedback with empty message');
   });
 
   it('throws when no client is set up', async () => {