Merge pull request #33376 from yuwata/strv_sort_uniq

strv: introduce strv_sort_uniq()

diff --cc src/basic/strv.c
Simple merge

diff --cc src/basic/strv.h
Simple merge

diff --cc src/test/test-strv.c
Simple merge

diff --cc src/varlinkctl/varlinkctl.c
Simple merge