[mlir][arith] fix canonicalization of mulsi_extended for i1 (#90150)

There is the `MulSIExtendedRHSOne` canonicalization for
arith.mulsi_extended that is defined as follows: `mulsi_extended(x, 1)
-> [x, extsi(cmpi slt, x, 0)]`. In the implementation of this, there is
a `IsScalarOrSplatOne` constraint for the second argument. However, this
constraint does not correctly handle situation when multiplying i1
values. Therefore, an additional constraint has been added which checks
the second argument for strict positivity.

fix #88732