mkosi: Use bash to execute command -v

command is only an executable on Fedora due to a downstream patch,
on Arch for example it's only a builtin so we have to use bash to
execute command -v to get proper results on Arch.

mkosi.sanitizers/mkosi.postinst

@@ -93,7 +93,7 @@ wrap=(
 )
 
 for bin in "${wrap[@]}"; do
-    if ! mkosi-chroot command -v "$bin" >/dev/null; then
+    if ! mkosi-chroot bash -c "command -v $bin" >/dev/null; then
         continue
     fi
 
@@ -103,7 +103,7 @@ for bin in "${wrap[@]}"; do
         enable_lsan=0
     fi
 
-    target="$(mkosi-chroot command -v "$bin")"
+    target="$(mkosi-chroot bash -c "command -v $bin")"
 
     mv "$BUILDROOT/$target" "$BUILDROOT/$target.orig"