fix: should only filter installed packages for optimization (#517)

Co-authored-by: Anthony Fu <github@antfu.me>

Author: Jungzl

src/core/unplugin.ts

@@ -1,3 +1,4 @@
+import { isPackageExists } from 'local-pkg'
 import { minimatch } from 'minimatch'
 import { slash } from '@antfu/utils'
 import { createUnplugin } from 'unplugin'
@@ -29,7 +30,7 @@ export default createUnplugin<Options>((options) => {
         const exclude = config.optimizeDeps?.exclude || []
 
         const imports = new Set((await ctx.unimport.getImports()).map(i => i.from)
-          .filter(i => i.match(/^[a-z@]/) && !exclude.includes(i)))
+          .filter(i => i.match(/^[a-z@]/) && !exclude.includes(i) && isPackageExists(i)))
 
         if (!imports.size)
           return