[mlir] Allow dense array to be parsed with type elision

This patch makes parsing dense arrays with type elision work properly.
If a ranked tensor type is supplied to `parseAttribute` on a dense
array, the element type is skipped. Moreover, if type elision is set to
`AttrTypeElision::Must`, the element type is elided.

For example, this allows

```
memref.global @z : memref<3xi32> = array<1, 2, 3>
```

Fixes #57433

Depends on D132758

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D132964