Remove unnecessary core/sed from pkg_build_deps

sed is already available in the Habitat Studio base environment,
so an explicit dependency is not required.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Signed-off-by: nikhil2611 <ngupta@progress.com>

Author: nikhil2611

habitat/plan.sh

@@ -6,7 +6,6 @@ ruby_pkg="core/ruby3_4"
 pkg_deps=(${ruby_pkg} core/coreutils core/libarchive)
 pkg_build_deps=(
   core/make
-  core/sed
   core/gcc
   core/git
 )