increasing the amount of in memory room keys that are processed at once

- 500 balanced memory with performance from my testing

matrix/services/crypto/src/main/kotlin/app/dapk/st/matrix/crypto/internal/RoomKeyImporter.kt

@@ -86,7 +86,7 @@ class RoomKeyImporter(
                                 isExported = true,
                             )
                         }
-                        .chunked(50)
+                        .chunked(500)
                         .forEach { onChunk(it) }
                 }
                 roomIds.toList().ifEmpty {