[PM-15907] Disable cipher key encryption on self-hosted instances (#5140)

* Disable cipher key encryption on self-hosted instances

* Removed override instead of setting to false

(cherry picked from commit 9b732c739a)

src/Core/Constants.cs

@@ -171,7 +171,6 @@ public static class FeatureFlagKeys
         return new Dictionary<string, string>()
         {
             { DuoRedirect, "true" },
-            { CipherKeyEncryption, "true" },
         };
     }
 }