make sure event exporting is happening on a background thread

app/src/main/kotlin/com/simplemobiletools/calendar/pro/helpers/IcsExporter.kt

@@ -28,6 +28,7 @@ class IcsExporter {
                 return@getFileOutputStream
             }
 
+            Thread {
                 if (showExportingToast) {
                     activity.toast(R.string.exporting)
                 }
@@ -71,6 +72,7 @@ class IcsExporter {
                     eventsFailed > 0 -> EXPORT_PARTIAL
                     else -> EXPORT_OK
                 })
+            }.start()
         }
     }