Fix CI build failure: replace invalid libCZI GIT_TAG reference

[Copilot]

The "Build Binaries (ubuntu-24.04)" CI job was failing with fatal: invalid reference: jbl/XT because modules/libCZI.cmake referenced a private fork branch that doesn't exist as a resolvable git ref.

Changes

• modules/libCZI.cmake: Switch from private fork (ptahmose/libCZI) to the official ZEISS upstream (ZEISS/libczi), and replace the invalid jbl/XT branch ref with a pinned commit hash for reproducible builds

# Before
GIT_REPOSITORY https://github.com/ptahmose/libCZI.git
GIT_TAG        jbl/XT

# After
GIT_REPOSITORY https://github.com/ZEISS/libczi
GIT_TAG        f8f0ccc12f8193a22bf5a093f4f29f75ffc05a7a