guix: bump time-machine to f0bb724211872cd6158fce6162e0b8c73efed126

Includes:
LLVM 18.1.x (#30201)
GCC 13.x (#29881)

git-minimal 2.41.0 -> 2.45.1
Kernel Headers 6.1.80 -> 6.1.92
moreutils 0.68 -> 0.69

Commits like
https://git.savannah.gnu.org/cgit/guix.git/commit/?id=7b0f145802f0c2c785014293d748721678fef824,
which should improve the bootstrap situation (#30042).

contrib/guix/libexec/prelude.bash

@@ -51,7 +51,7 @@ fi
 time-machine() {
     # shellcheck disable=SC2086
     guix time-machine --url=https://git.savannah.gnu.org/git/guix.git \
-                      --commit=dc4842797bfdc5f9f3f5f725bf189c2b68bd6b5a \
+                      --commit=f0bb724211872cd6158fce6162e0b8c73efed126 \
                       --cores="$JOBS" \
                       --keep-failed \
                       --fallback \