internal/config: remove usage of test := test

It's 2026 :)

Author: fsouza

internal/config/config_test.go

@@ -684,7 +684,6 @@ func TestEnvVarOrDefault(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		test := test
 		t.Run(test.name, func(t *testing.T) {
 			// Set up environment
 			beforeEnv := os.Environ()