[i18n] Add irregular pluralizations

[obulat]

Problem

Some languages have more than one plural noun form that correspond to different numbers. We need to set up the pluralization for languages other than Russian.

Description

Vue-i18n uses the pluralization config to select the correct form, and here is the example implementation for Russian:
https://github.com/WordPress/openverse-frontend/blob/0f784f4df9fdf4b460dab387f0877229420efebc/src/plugins/vue-i18n.js#L11-L30
This corresponds to the following config in the .po format:
"pluralExpression": "(n % 10 == 1 && n % 100 != 11) ? 0 : ((n % 10 >= 2 && n % 10 <= 4 && (n % 100 < 12 || n % 100 > 14)) ? 1 : 2)",

It is OK to create one PR per single locale group with the same pluralExpression, one from the following list:

Locales:

• Arabic ar, Algerian Arabic arq, Moroccan Arabic ary
• Bengali (India) bn_IN, Breton bre, Persian (Afghanistan) fa_AF, Persian fa_IR, French (Belgium) fr_BE, French (Canada) fr_CA, French (France) fr_FR, Arpitan frp, Borana-Arsi-Guji Oromo gax, Indonesian id_ID, Kabyle kab, Lingala lin, Maori mri, Occitan oci, Picard pcd, Portuguese (Brazil) pt_BR, Saraiki skr, Tahitian tah, Turkish tr_TR, Turkmen tuk, Tamazight (Central Atlas) tzm
• Cornish cor
• Czech cs_CZ, Slovak sk_SK
• Welsh cy
• Lower Sorbian dsb, Upper Sorbian hsb, Slovenian `sl_SI
• Irish ga
• Scottish Gaelic gd
• Icelandic is_IS', 'Macedonian mk_MK
• Lithuanian lt_LT
• Latvian lv
• Montenegrin me_ME
• Polish pl_PL
• Romanian ro_RO
• Silesian szl
• Tamazight zgh

These locales use a single version, so probably don't need any pluralization set up?

• Emoji art_xemoji, Balochi Southern bcc, Tibetan bo, Dzongkha dzo, Igbo ibo, Japanese ja, Georgian ka_GE, Kyrgyz kir, Khmer km, Korean ko_KR, Lao lo, Mauritian Creole mfe, Malay ms_MY, Rohingya rhg, Sundanese su_ID, Thai th, Tigrinya tir, Tatar tt_RU, Uzbek uz_UZ, Vietnamese vi, Wolof wol, Chinese (China) zh_CN, Chinese (Hong Kong) zh_HK, Chinese (Singapore) zh_SG, Chinese (Taiwan) zh_TW

These locales should use the same rules as Russian:

• Belarusian bel, Ukrainian uk, Serbian sr_RS, Croatian hr, Bosnian bs_BA

Additional context

To get the .po format pluralization rules, run pnpm run dev. This should create a src/locales/scripts/wp-locales.json file, with an object with locale properties for all available locales. Only the locales with irregular plurals have the "pluralExpression" property.

Implementation

• 🙋 I would be interested in implementing this feature.