Use the same logLevel globally

Currently, tsup's logs are very confusing, there are [its own](https://github.com/egoist/tsup/blob/d428ce7be1/src/log.ts), there are various plugins (such as esbuild, [svelte](https://github.com/egoist/tsup/blob/d428ce7be1341fe7c8d6f745eaa0676f9eeeea89/src/esbuild/svelte.ts#L84)), which can easily lead to developers accidentally [break the consistency of the log](https://github.com/egoist/tsup/blob/d428ce7be1341fe7c8d6f745eaa0676f9eeeea89/src/esbuild/svelte.ts#L99), it is time to unify them.