Fix typo in encryption error message

resources/langs/nheko_cs.ts

resources/langs/nheko_de.ts

resources/langs/nheko_el.ts

resources/langs/nheko_en.ts

resources/langs/nheko_et.ts

resources/langs/nheko_fi.ts

resources/langs/nheko_fr.ts

resources/langs/nheko_it.ts

resources/langs/nheko_ja.ts

resources/langs/nheko_nl.ts

resources/langs/nheko_pl.ts

resources/langs/nheko_ro.ts

resources/langs/nheko_ru.ts

resources/langs/nheko_si.ts

resources/langs/nheko_zh_CN.ts

src/timeline/EventStore.cpp