Refactor trace package tests for improved readability

- Removed unnecessary blank lines in multiple test files to enhance code clarity and maintainability.
- Adjusted formatting in `subscription.go`, `trace_bench_test.go`, `trace_concurrent_test.go`, `trace_mem_test.go`, `trace_node_test.go`, `trace_space_test.go`, and `trace_subscription_test.go` for consistency.

trace/trace_bench_test.go

@@ -491,4 +491,3 @@ func getTraceScenarios() []traceScenario {
 		},
 	}
 }
-

trace/trace_concurrent_test.go

@@ -282,4 +282,3 @@ func TestConcurrentLogging(t *testing.T) {
 		})
 	}
 }
-

trace/trace_mem_test.go

@@ -618,4 +618,3 @@ func TestGoroutineLeak(t *testing.T) {
 		t.Logf("✓ No goroutine leak detected")
 	}
 }
-

trace/trace_node_test.go

@@ -211,4 +211,3 @@ func TestCompleteWithOutput(t *testing.T) {
 		})
 	}
 }
-

trace/trace_space_test.go

@@ -183,4 +183,3 @@ func TestSpaceGetSpace(t *testing.T) {
 		})
 	}
 }
-

trace/trace_subscription_test.go

@@ -280,4 +280,3 @@ func TestMultipleSubscribers(t *testing.T) {
 		})
 	}
 }
-