chore: simplify Rslib build config

Author: chenjiahan

rslib.config.ts

@@ -3,12 +3,9 @@ import { defineConfig } from '@rslib/core';
 export default defineConfig({
   lib: [
     { format: 'esm', syntax: 'es2021', dts: true },
-    { format: 'cjs', syntax: 'es2021', dts: true },
+    { format: 'cjs', syntax: 'es2021' },
   ],
   source: {
     tsconfigPath: './tsconfig.build.json',
   },
-  output: {
-    sourceMap: false,
-  },
 });