fix(fresh/plugin-vite): fix staticFiles path encode ([#3657](https://github.com/denoland/fresh/issues/3657))

[LY1806620741]

fix #3657

1. fresh-build:
   a. prepareStaticFile() 函数 转化test %20encodeUri 为test%20%20encodeUri，而非 test%20%2520encodeUri 的问题.
   prepareStaticFile() function converts test %20encodeUri to test%20%20encodeUri, instead of test%20%2520encodeUri
   b. staticFiles 路径编码与 freshServeStaticFiles() 函数存在重复编码问题.
   There is a double encoding issue caused by duplicate path encoding logic between staticFiles and the freshServeStaticFiles() function
2. fresh-vite-plugin:
   a. devServer 中通过 urlpath 读取系统文件时的路径转编码异常问题
   Path encoding conversion error when devServer reads system files via urlpath