* add URL support to Label element and XML parsing
* refactor Label URL handling to use getter method in setURL
* implement URL opening confirmation dialog and platform-specific URL handling
* fix: fixed build errors
* remove: delete test link label from worlds.xml
* refactor: remove URL handling from Label class and XML parsing
* refactor: clean up Label class by removing unnecessary whitespace and improving code readability
* refactor: remove unused URL member from Label class
* refactor: remove unused URL attribute from XML UI documentation and related code
* refactor: improve code readability by adding whitespace and formatting adjustments in Label class
* refactor: improve whitespace consistency in Label class and add URL opening functionality in libcore
