editors/libreoffice: update to 7.2.1 release (+)

LibreOffice 7.2.1 is here, with many bugfixes and compatibility improvements.
Learn more about it: https://blog.documentfoundation.org/blog/2021/09/16/libreoffice-7-2-1-community/

• Add OPTION to build GTK4 VCL
• If both GTK3 and KF5 enabled, add GTK3_KDE5 VCL to build
• Force RUN_DEPENDS on JDK if JAVA selected to run extensions