fix(plugin-vue): avoid duplicate import, fix #2640 (#2897)

Author: ygj6

packages/plugin-vue/src/main.ts

@@ -143,10 +143,10 @@ export async function transformMain(
   // SSR module registration by wrapping user setup
   if (ssr) {
     output.push(
-      `import { useSSRContext } from 'vue'`,
+      `import { useSSRContext as __vite_useSSRContext } from 'vue'`,
       `const _sfc_setup = _sfc_main.setup`,
       `_sfc_main.setup = (props, ctx) => {`,
-      `  const ssrContext = useSSRContext()`,
+      `  const ssrContext = __vite_useSSRContext()`,
       `  ;(ssrContext.modules || (ssrContext.modules = new Set())).add(${JSON.stringify(
         filename
       )})`,