Add type hints and clearer type error for passing non-strings to IssueCommand.
Add type hints and clearer type error for passing non-strings to IssueCommand.

PiperOrigin-RevId: 391157453

GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker