Remove unnecessary jquery-ui-1.12.1.zip from DISTFILES
jquery-ui-1.21.1 is already bundled in the matplot 2.2.4 tarball [1].
This patch fixes r496681.
[1] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236455#c4
PR: 236740
Submitted by: sunpoet (myself)
Approved by: maintainer (timeout, 14 days)