Remove unnecessary messages (#15109)

app/javascript/mastodon/locales/ar.json

app/javascript/mastodon/locales/ast.json

app/javascript/mastodon/locales/bg.json

app/javascript/mastodon/locales/bn.json

app/javascript/mastodon/locales/br.json

app/javascript/mastodon/locales/ca.json

app/javascript/mastodon/locales/co.json

app/javascript/mastodon/locales/cs.json

app/javascript/mastodon/locales/cy.json

app/javascript/mastodon/locales/da.json

app/javascript/mastodon/locales/de.json

app/javascript/mastodon/locales/defaultMessages.json

app/javascript/mastodon/locales/el.json

app/javascript/mastodon/locales/en.json

app/javascript/mastodon/locales/eo.json

app/javascript/mastodon/locales/es-AR.json

app/javascript/mastodon/locales/es.json

app/javascript/mastodon/locales/et.json

app/javascript/mastodon/locales/eu.json

app/javascript/mastodon/locales/fa.json