Allow optional `stablehlo.broadcast_in_dim` op.
Allow optional `stablehlo.broadcast_in_dim` op.

When deferring `stablehlo.transpose` of the lhs of `stablehlo.add`, the rhs may have a `constant->broadcast_in_dim` pattern.
Allow the pattern `DeferActivationTransposeForAddOp` to handle such a case.
