[napi] It's hard to distinguish `Builtin` error due to `err.to_string()` and no way to get `is_runtime_module`

[JounQin]

oxc-resolver/src/error.rs

Lines 54 to 55 in 6a92459

	#[error("Builtin module {resolved}")]
	Builtin { resolved: String, is_runtime_module: bool },

oxc-resolver/napi/src/lib.rs

Line 54 in 6a92459

error: Some(err.to_string()),

We had to do something like resolver.error?.startsWith('Builtin module '), which is very strange IMO.