[mlir] feat(vector): drop unit dims from memrefs for xfer_read/write for non… (PR #187076)

[Andrzej Warzyński]

https://github.com/banach-space approved this pull request.

LG % nits, thanks for the fix!

Could you update the title? It is usually something like:
```
[mlir][vector] Implement XYZ
```

Also, right now it does not fit within GitHub limits :)

https://github.com/llvm/llvm-project/pull/187076