fix: dir export with trailing comma

[westhide]

Description

when genarate exports from dirs , if the export statement have a trailing comma , unimport.modifyDynamicImports() will contain a blank name export (const : typeof import('./export')[''])

To fix this case, filter the exports with name!==''

Linked Issues

Additional context

Maybe this problem should resolve through fix the modifyDynamicImports function which from unjs/unimport ?

[antfu]

Nice catch! Probably better to fix in mlly with https://github.com/unjs/mlly/blob/df908fd509d7357265038b5fec414c41bd3ebd67/src/analyze.ts#L95

Thanks

[westhide]

upstream PR merged ,this commit can be closed

related unjs/mlly#59