Subscribing to communities that are unknown to an instance requires running LASIM upload twice

[CMahaff]

Describe the Bug
This issue is basically the same thing that actual users run into on a fresh instance when they are the first person to lookup a specific community for the first time.

At first, it isn't known by the server, but once you search it, the server learns about it.

In LASIM this manifests initially as a failure, but re-running LASIM upload after giving the server a minute or two allows it to succeed. See redacted log output below.

Information
LASIM Version: 0.1.2
LASIM Profile Version: 1
Lemmy Source Instance URL: N/A
Lemmy Source Instance Version: N/A
Lemmy Target Instance URL: N/A
Lemmy Target Instance Version: 0.18.2

Output of LASIM
First Run Output

Logging in as <redacted>
Login Successful.
Existing Settings Downloaded. Calculating delta...
All profile settings from the original profile will be applied.
1 new users will be blocked
7 new communities will be blocked
80 new communities will be followed
Cannot find community <redacted>, got exception HTTP status client error (400 Bad Request)
Cannot find community <redacted>, got exception HTTP status client error (400 Bad Request)
Cannot find community <redacted>, got exception HTTP status client error (400 Bad Request)

Finished!

Second Run Output

Logging in as <redacted>
Login Successful.
Existing Settings Downloaded. Calculating delta...
All profile settings from the original profile will be applied.
0 new users will be blocked
0 new communities will be blocked
3 new communities will be followed
Finished!