t: add test for git refs list subcommand

Add a test script, `t/t1461-refs-list.sh`, for the new `git refs list` command. This script acts as a simple driver, leveraging the shared test library created in the preceding commit. It works by overriding the `$git_for_each_ref` variable to "git refs list" and then sourcing the shared library (`t/for-each-ref-tests.sh`). This approach ensures that `git refs list` is tested against the entire comprehensive test suite of `git for-each-ref`, verifying that it acts as a compatible drop-in replacement. Mentored-by: Patrick Steinhardt <ps@pks.im> Mentored-by: shejialuo <shejialuo@gmail.com> Mentored-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Meet Soni <meetsoni3017@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>