fix(runtime): derive unattributed cost from usage status

src/main/worker/entry/index.ts

@@ -108,7 +108,6 @@ function cancelRun(runId: string) {
       signal: null,
       model: null,
       usageStatus: "aborted_before_usage",
-      unattributedCost: true,
       inputTokens: null,
       outputTokens: null,
     });