fix: loadFile ignore ts extend on readFileSync (#294)

eggjs/tegg#283

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Bug Fixes**
- Updated the file loading functionality to properly differentiate
TypeScript files from other file types. This modification prevents
unintended processing behavior for TypeScript content, ensuring more
reliable file operations and enhancing overall stability in handling
various file formats.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: fengmk2

src/utils/index.ts

@@ -78,7 +78,7 @@ export default {
     try {
       // if not js module, just return content buffer
       const extname = path.extname(filepath);
-      if (extname && !extensionNames.includes(extname)) {
+      if (extname && !extensionNames.includes(extname) && extname !== '.ts') {
         return fs.readFileSync(filepath);
       }
       const obj = await importModule(filepath, { importDefaultOnly: true });