fix: --stat's path argument is not optional

[k-yle]

If --stat is invoked without the path argument, then mergedConfig.stat becomes a boolean, and causes the program to crash here:

ts-bulk-suppress/src/index.ts

Lines 136 to 138 in fddfb18

	if (mergedConfig.stat) {
	writeJSONSync(mergedConfig.stat, projectStat, { spaces: 2 });
	}

[CLAassistant]

All committers have signed the CLA.

[octogonz]

Thanks @k-yle !