[Backport release-24.11] gitbutler: 0.14.4 -> 0.14.7

[nixpkgs-ci]

Bot-based backport to release-24.11, triggered by a label in #381388.

• Before merging, ensure that this backport is acceptable for the release.
  • Even as a non-commiter, if you find that it is not acceptable, leave a comment.

[getchoo]

error: builder for '/nix/store/jwmriacvc36iw9g6fycdhn0jfpmw2bjy-gitbutler-0.14.7.drv' failed with exit code 1;
       last 25 log lines:
       >       - /nix/store/829n7i53bkcgfhvjpjdwhf5qbapndyhq-libSM-1.2.4-dev/lib/pkgconfig
       >       - /nix/store/8p0cmfwq92g0js7d56m74jnrdhqy310x-libXcomposite-0.4.6-dev/lib/pkgconfig
       >       - /nix/store/b057psay044rqlqzhrv47kymmf3sr00s-libXfixes-6.0.1-dev/lib/pkgconfig
       >       - /nix/store/5m1i8h8qk76i065ag5rdsbnkhpl9z1yk-libXcursor-1.2.2-dev/lib/pkgconfig
       >       - /nix/store/q5lw4xhv5pz1g1bz27q3p5w2fi49n7rk-libXdamage-1.1.6-dev/lib/pkgconfig
       >       - /nix/store/519hbmr99fhnyb9r61wx15h7yddxynns-libXi-1.8.2-dev/lib/pkgconfig
       >       - /nix/store/nhl5l0c348v0ljcy06xdj632pywq16a1-libXrandr-1.5.4-dev/lib/pkgconfig
       >       - /nix/store/xrnwmmb63d60avxsj7nrpj0yqqjrk4zs-libglvnd-1.7.0-dev/lib/pkgconfig
       >       - /nix/store/br81aqrvkrlihs2ar44l1c9f8zmv97qh-wayland-protocols-1.38/share/pkgconfig
       >       - /nix/store/adrvd272z7r3sb8cqybxg0iyvyzkad4a-libXinerama-1.1.5-dev/lib/pkgconfig
       >       - /nix/store/0mg1sba8jz1ya9c25lcbhf50lix9c69p-cups-2.4.11-dev/lib/pkgconfig
       >       - /nix/store/1s5g5sj2mpmazvbcrfw63xjdslvcjcag-gmp-with-cxx-6.3.0-dev/lib/pkgconfig
       >       - /nix/store/iyp2w9yasrigsxfch86y7ykj2xf55bwh-libsoup-3.6.1-dev/lib/pkgconfig
       >
       >   HINT: you may need to install a package such as libgit2, libgit2-dev or libgit2-devel.
       >
       >
       >   --- stderr
       >   thread 'main' panicked at /build/gitbutler-0.14.7-vendor/libgit2-sys-0.18.0+1.9.0/build.rs:45:13:
       >   The environment variable `LIBGIT2_NO_VENDOR` has been set but no compatible system libgit2 could be found.
       >   The build is now aborting. To disable, unset the variable or use `LIBGIT2_NO_VENDOR=0`.
       >
       >   note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
       > warning: build failed, waiting for other jobs to finish...
       >     Error failed to build app:
       For full logs, run 'nix log /nix/store/jwmriacvc36iw9g6fycdhn0jfpmw2bjy-gitbutler-0.14.7.drv'.

Seems libgit2 in 24.11 is too old. We should be able to just let Rust vendor it, or override it here locally 🤷