storage: TestIntegration_UniverseDomains_SignedURL_DefaultSignBytes failed

This test failed! To configure my behavior, see [the Flaky Bot documentation](https://github.com/googleapis/repo-automation-bots/tree/main/packages/flakybot). If I'm commenting on this issue too often, add the `flakybot: quiet` label and I will stop commenting. --- commit: bb2a8df0ad048e29a41c5cd8d8dce8c0a282f8d1 buildURL: [Build Status](https://source.cloud.google.com/results/invocations/9e71880a-3e67-4d04-9758-9c1050eb668b), [Sponge](http://sponge2/9e71880a-3e67-4d04-9758-9c1050eb668b) status: failed