Add retrys to fetching translation strings

[jhnstn]

I've noticed this error when trying to prepare GBM:

Could not find translation file https://translate.wordpress.org/projects/wp-plugins/jetpack/dev/es-cr/default/export-translations/?format=json for project slug wp-plugins/jetpack
/private/var/folders/m3/zr93ff4x0fx8kvpbh_b4sqb40000gn/T/gbm-2745483336/gutenberg/packages/react-native-editor/bin/i18n-translations-download.js:139
			( result ) => result.response```

It seems intermitent so I'm thinking we should retry the `npm run i18n:update` command a few times before failing the entire run.