refactor(storage): fix ESLint and TS errors in internal tooling and conformance tests

[thiyaguk09]

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Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Code Review

This pull request introduces formatting updates and asynchronous handling improvements across the storage performance and conformance tests, such as awaiting bucket deletion, returning promises in cleanup routines, and using the void operator for unawaited main calls. The review feedback suggests simplifying performTestCleanup using a ternary operator to avoid manual type casting, handling potential errors in recordResult with a .catch() block instead of silencing it with void, and replacing the platform-dependent execSync call in performanceUtils.ts with native Node.js APIs to prevent command injection and ensure cross-platform compatibility.