feat: Translate frontend/src/i18n/en.json in bg

86% of minimum 50% translated source file: 'frontend/src/i18n/en.json'
on 'bg'.

Sync of partially translated files: 
untranslated content is included with an empty translation 
or source language content depending on file format

frontend/src/i18n/bg.json

@@ -227,7 +227,7 @@
     "settingsUpdated": "Настройките са обновени!",
     "shareDuration": "Продължителност на споделянето",
     "shareManagement": "Управление на споделянето",
-    "shareDeleted": "Share deleted!",
+    "shareDeleted": "Споделянето е премахнато!",
     "singleClick": "Use single clicks to open files and directories",
     "themes": {
       "default": "System default",