Bug: Bookmark page shows wrong empty state when no bookmarks exist

[uxbyweng]

Description

On the bookmark page, there is an issue with the empty state when no bookmarks have been saved yet.

Currently, two messages are displayed:

• There are no Bookmarks yet!
• No flashcards yet... start to add one.

In addition, a button Add a new flashcard is shown. This behavior is misleading in the bookmark context.

Current behavior

If no bookmarks exist, the page shows:

• the message There are no Bookmarks yet!
• an additional flashcard-related message
• the button Add a new flashcard

Expected behavior

If no bookmarks exist, the page should show only one message:

• There are no Bookmarks yet!

This message should be styled consistently with the existing feedback message component, for example:

<FeedbackMessage role="status" aria-live="polite">
  There are no Bookmarks yet!
</FeedbackMessage>

The "Add a new flashcard" button should not be displayed in this case.

Acceptance criteria

• If no bookmarks are saved, only one empty-state message is displayed.
• The message text is: There are no Bookmarks yet!
• The message uses the FeedbackMessage component styling.
• The message is not displayed in the current red text styling.
• No additional flashcard-related message is shown.
• The Add a new flashcard button is not shown on the bookmark page empty state.