Fix type of bmat_gradient

src/components/gradient_waveforms/no_gradient_blocks.jl

@@ -25,7 +25,7 @@ end
 end
 
 @defvar gradient begin
-    bmat_gradient(::NoGradient) = zero(SMatrix{3, 3, 9, Float64})
+    bmat_gradient(::NoGradient) = zero(SMatrix{3, 3, Float64, 9})
     bmat_gradient(ngb::NoGradient, qstart::VariableType) = qstart^2 * variables.duration(ngb)
     bmat_gradient(ngb::NoGradient, qstart::AbstractVector{<:VariableType}) = @. qstart * permutedims(qstart) * variables.duration(ngb)
 end