po-gettext formatter could not correctly handle plural inside a trans

Description

When using both Trans and Plural react macros, gettext formatter does not capture the inner Plural rule properly and instead formats using ICU format.

Verifications

• I've checked the docs and this isn't covered there.
• I've searched existing issues on GitHub.

Reproduction Steps

        <Trans>
          Trans with plural inside
            <Plural
            value={count}
            zero={"There are no items"}
            one={"There's one item"}
            other={"There are # items"}
          />
        </Trans>

Expected Behavior

Expected result:

Po file with:

msgid "There are no items"
msgid_plural "There are # items"
msgstr[0] "There are no items"
msgstr[1] "There's one item"
msgstr[2] "There are # items"

Actual:

msgid "Trans with plural inside{count, plural, zero {There are no items} one {There's one item} other {There are # items}}"
msgstr "Trans with plural inside{count, plural, zero {There are no items} one {There's one item} other {There are # items}}"

Macro Support

Babel with babel-macro-plugin

Lingui Version

5.2

Babel Version

No response

Framework

Create React app

Start with the gettext formatter's handling of Babel macro output and reproduce the nested Trans/Plural example from the issue. Add a formatter regression test; done means the generated PO content uses msgid/msgid_plural and separate plural translations instead of an ICU-formatted msgstr.