AUTH should not be dependent on dataset loading

[Kilowhisky]

Describe the bug
If you issue AUTH while the dataset is loading, it will return the error LOADING Tile38 is loading the dataset in memory.
This causes issues with some Redis libraries (cough StackExchange.Redis) that issue that command blindly and expect it to be respected.

To Reproduce

1. Create large AOF
2. Restart the server
3. Attempt to auth while loading the AOF

Expected behavior
It should AUTH successfully

Logs
NA

Operating System (please complete the following information):
NA

Additional context

Expect incoming PR