Bootstrap Doesn't Respect `--skip-po`

[NR]

```
Fetching gnulib PO files from https://translationproject.org/latest/
Last-modified header missing -- time-stamps turned off.
2025-06-05 03:06:27 URL:https://translationproject.org/latest/gnulib/
[7935/7935] -> "./index.html.tmp" [1]
<...>
```

`--skip-po                Do not download *.po files.`

```
$ GNULIB_SRCDIR="/<pathTo>/gnulib" \
  ./bootstrap \
    --skip-po \
    --no-git \
    --no-bootstrap-sync
```

I expect it relates to `bootstrap.conf`:
`gnulib_tool_option_extras="--makefile-name=gnulib.mk
--po-base=gnulib_po --po-domain=wget"`
vs sed's:
`gnulib_tool_option_extras="--tests-base=gnulib-tests --with-tests
--symlink --makefile-name=gnulib.mk --automake-subdir`

bootstrap:
```
  if $use_gnulib; then
    gnulib_tool_options="\
     --no-changelog\
     --aux-dir=$build_aux\
     --doc-base=$doc_base\
     --lib=$gnulib_name\
     --m4-base=$m4_base/\
     --source-base=$source_base/\
     --tests-base=$tests_base\
     --local-dir=$local_gl_dir\
     $gnulib_tool_option_extras\
    "
```

Once the `--po-*` elements of that "extras" var is removed, bootstrap continues.