[3.13] gh-129061: Fix `FORCE_COLOR` and `NO_COLOR` when empty strings (GH-129140) (#129360)

gh-129061: Fix `FORCE_COLOR` and `NO_COLOR` when empty strings (GH-129140)
(cherry picked from commit 9546fe2ef2db921709f3cb355b33bba977658672)

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>