Please remove Extra-Depends from gegl

[Jeremy Bícha <jbicha@debian.org>]

Please remove Extra-Depends: librsvg2-dev (>= 2.54.7+dfsg-2) from gegl
https://buildd.debian.org/status/package.php?p=gegl

I believe the only use of librsvg is in the one file
https://salsa.debian.org/gnome-team/gegl/-/blob/debian/latest/operations/external/svg-load.c
and that code is specifically designed to work with older versions of
librsvg. (librsvg now uses Rust and some ports haven't been able to
build it yet.)

>From build logs, it looks like that Extra-Depends was added earlier
this year but that file hasn't changed since 2023.

Thank you,
Jeremy Bícha