[js/web] JSEP Expand fix for inputs with rank < 2 (#16829)
### Description
If Expand inputs has rank < 2, `inputIndicesHelper` and
`outputIndicesHelper` create indices as u32 instead if array<u32> and
`calculateInputIndex` throws an error
### Motivation and Context
I've encountered this error while making StableDiffusion work with JSEP
