Fixed issue with sound effects loading — HellEscape Steam update #814182

Background: Got a report about serious lags while playing sounds for the first time (which cause them to load). After investigation I found out that using `AudioContext` to verify sound asset can cause strange issues with some sound devices. Decided to drop it since its not critical + preload all sound assets for smoother experience. Changes: - Fixed sound-loading issue on some devices. - Will now pre-load sound assets to make sounds play more smoothly on first time (can be disabled via config). Please let me know if any issues related to sounds or game loading arise. Thanks!