chore: Stop using `Livechat_Room_Count` setting (#35017)

apps/meteor/app/livechat/server/lib/QueueManager.ts

apps/meteor/server/settings/omnichannel.ts

packages/i18n/src/locales/af.i18n.json

packages/i18n/src/locales/ar.i18n.json

packages/i18n/src/locales/az.i18n.json

packages/i18n/src/locales/be-BY.i18n.json

packages/i18n/src/locales/bg.i18n.json

packages/i18n/src/locales/bs.i18n.json

packages/i18n/src/locales/ca.i18n.json

packages/i18n/src/locales/cs.i18n.json

packages/i18n/src/locales/cy.i18n.json

packages/i18n/src/locales/da.i18n.json

packages/i18n/src/locales/de-AT.i18n.json

packages/i18n/src/locales/de-IN.i18n.json

packages/i18n/src/locales/de.i18n.json

packages/i18n/src/locales/el.i18n.json

packages/i18n/src/locales/en.i18n.json

packages/i18n/src/locales/eo.i18n.json

packages/i18n/src/locales/es.i18n.json

packages/i18n/src/locales/fa.i18n.json