Generated TS file with plural forms contain incorrect <numerusform> entry count

TS files with translatable strings containing plurals should include the correct number of <numerusform> entries for the target language plural forms.

The qt_add_translations() command is generating .ts files containing only one <numerusform> entry.

Same behavior also observed when generating a plurals-only .ts file via the qt_add_lupdate(PLURAL_TS_FILE file.ts) and qt_add_translations(PLURAL_TS_FILE file.ts) commands.

Possible related bug QTBUG-127789, since setting the language attribute in the generated .ts file and rebuilding the project with lupdate_translations leads to the file being updated to include the correct number of <numerusform> entries for the target language.

To reproduce issue, build attached project with update_translations.