fix test for sparse matrix assignment (#32756)

(cherry picked from commit 30b3636)

Author: dkarrasch

stdlib/SparseArrays/test/sparse.jl

@@ -93,7 +93,10 @@ do33 = fill(1.,3)
 end
 
 @testset "Issue #30006" begin
-    SparseMatrixCSC{Float64,Int32}(spzeros(3,3))[:, 1] == [1, 2, 3]
+    A = SparseMatrixCSC{Float64,Int32}(spzeros(3,3))
+    A[:, 1] = [1, 2, 3]
+    @test nnz(A) == 3
+    @test nonzeros(A) == [1, 2, 3]
 end
 
 @testset "concatenation tests" begin