Undo modernized sleep

Tests/ScryfallKitTests/SmokeTests.swift

@@ -168,7 +168,7 @@ final class SmokeTests: XCTestCase {
             page += 1
             results = try await client.searchCards(filters: [filter], page: page)
             checkForUnknowns(in: results.data)
-            try await Task.sleep(for: .milliseconds(500))
+            usleep(500000) // Wait for 0.5 seconds
         }
     }