devel/iniparser: Update to 4.3.0
- Add tests: Unity is fetched at configure time, which needs network access. Add it as a second distfile and set FETCHCONTENT_SOURCE_DIR_UNITY instead. This skips the PATCH_COMMAND that places unity_config.h, so copy it in pre-test.
ChangeLog:
https://gitlab.com/iniparser/iniparser/-/releases/v4.3.0#430-2026-09-15