tfexec/WorkspaceListJSON: Remove unused reattachment code (#617)

tfexec/workspace_list.go

diff --git a/tfexec/workspace_list.go b/tfexec/workspace_list.go
index e9da69b..cc32e59 100644
--- a/tfexec/workspace_list.go
+++ b/tfexec/workspace_list.go
@@ -114,15 +114,6 @@
 		o.configureWorkspaceList(&c)
 	}
 
-	mergeEnv := map[string]string{}
-	if c.reattachInfo != nil {
-		reattachStr, err := c.reattachInfo.marshalString()
-		if err != nil {
-			return nil, err
-		}
-		mergeEnv[reattachEnvVar] = reattachStr
-	}
-
 	args := []string{"workspace", "list", "-json"}
 	return tf.buildWorkspaceListCmd(ctx, c, args)
 }