[mlir][vector][nfc] Simplify `in_bounds` attr update (#100334)

Since the `in_bounds` attribute is mandatory, there's no need for logic
like this (`readOp.getInBounds()` is guaranteed to return a non-empty
ArrayRef):

```cpp
ArrayAttr inBoundsAttr = readOp.getInBounds()
    ? rewriter.getArrayAttr( readOp.getInBoundsAttr().getValue().drop_back(dimsToDrop))
    : ArrayAttr();
```

Instead, we can do this:
```cpp
ArrayAttr inBoundsAttr = rewriter.getArrayAttr(
    readOp.getInBoundsAttr().getValue().drop_back(dimsToDrop));
```

This is a small follow-up for #97049 - this change should've been
included there.

0 files changed, 0 insertions, 0 deletions