Update error_path_manager_timeout.jl

Author: DilumAluthge

test/error_path_manager_timeout.jl

@@ -40,7 +40,8 @@ mktempdir() do tmpdir
     expected_inner_ex_T = ErrorException
     expected_inner_ex_INSTANCE = ErrorException("launch_timeout exceeded")
     mgr = SlurmClusterManager.SlurmManager(; launch_timeout = 2.0)
-    observed_outer_ex = @test_throws expected_outer_ex_T Distributed.addprocs(mgr)
+    test_result = @test_throws expected_outer_ex_T Distributed.addprocs(mgr)
+    observed_outer_ex = test_result.value
     @info "" observed_outer_ex # TODO: Delete this line
     @show dump(observed_outer_ex) # TODO: Delete this line
     @test observed_outer_ex isa expected_outer_ex_T