fix test data: use correct provider key in setup test

Task 9 resolved (removed stale docs).
Provider key 'attack-on-titan' replaced with 'test-unknown-anime-2020'.

tests/robot/api/setup.robot

@@ -30,6 +30,6 @@ Get Unresolved Folder Details
 
 Resolve Folder With Provider Key
     [Documentation]    Resolve an unresolved folder by mapping it to a provider key.
-    ${resp}=    Resolve Folder    Unknown Anime (2020)    attack-on-titan
+    ${resp}=    Resolve Folder    Unknown Anime (2020)    test-unknown-anime-2020
     Response Should Have Status    ${resp}    200
     Response Should Be Valid JSON    ${resp}