Fix "Copy to" preferences

[paudelritij]

Closes #12843

This pull request addresses an issue where the dialog prompting users about including cross-references reappears even after the user has selected the "Do not ask again" option. Additionally, it resolves the problem of the updated state of preferences not being saved correctly, ensuring that the last saved state persists across sessions.

• Use EasyBind.listen() in getCopyToPreferences to observe any change in these properties to save the preferences.
• Implemented property binding in CopyToPreferences class.

Screen Recordings:

sub-issue-1.mov

sub-issue-2.mov

Mandatory checks

• I own the copyright of the code submitted and I license it under the MIT license
• Change in CHANGELOG.md described in a way that is understandable for the average user (if change is visible to the user)
• [/] Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• [/] Screenshots added in PR description (if change is visible to the user)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[subhramit]

Screen recordings, please?

[subhramit]

Thank you!

[trag-bot]

@trag-bot didn't find any issues in the code! ✅✨