Third-party Integration Improvements

Added

• Added Support for Iframes and PDFs in lightbox link
• Added better compatibility with Third-party plugins which add toolbar items to Gutenberg
• Added better compatibility with Third-party themes Row block rendering
• Added new filter `nectar_custom_font_list` to allow manual addition of custom fonts from external sources

Fixed

• Fixed Size Control value issue
• Fixed Scrolling Marquee block duplication issue
• Fixed Updater to decrease checks
• Fixed Global Section in header nav bug
• Fixed Post Grid off by one error