fix(trace viewer): updating default traceStorageDir value
When `npx playwright show-trace <tracePath>` command is executed, without providing the `resources` optional parameter, the function expected the `traceStorageDir` default value to be the same directory as in which the tracePath resides. This change updates it to the `dirname(tracePath)/trace-resources` if it exists. Such a directory hirerachy is the default that is created when running the tracer in Playwright.
