fix: correct DiffRhythm workflow parameter order for all three workflows

Changed edit_segments from "[-1, 20], [60, -1]" to empty string "" at position 11.
This fixes validation errors where parameters were being interpreted as wrong types.

The correct 12-parameter structure is:
0: model (string)
1: style_prompt (string)
2: unload_model (boolean)
3: odeint_method (enum)
4: steps (int)
5: cfg (int)
6: quality_or_speed (enum)
7: seed (int)
8: edit (boolean)
9: edit_lyrics (string, empty)
10: edit_song (string, empty)
11: edit_segments (string, empty)

Updated workflows:
- diffrhythm-random-generation-v1.json
- diffrhythm-reference-based-v1.json
- diffrhythm-full-length-t2m-v1.json

🤖 Generated with Claude Code

Co-Authored-By: Claude <noreply@anthropic.com>

comfyui/workflows/text-to-music/diffrhythm-full-length-t2m-v1.json

@@ -32,7 +32,7 @@
         false,
         "",
         "",
-        "[-1, 20], [60, -1]"
+        ""
       ],
       "title": "DiffRhythm Full-Length Text-to-Music (4m45s)"
     },

comfyui/workflows/text-to-music/diffrhythm-random-generation-v1.json

@@ -32,7 +32,7 @@
         false,
         "",
         "",
-        "[-1, 20], [60, -1]"
+        ""
       ],
       "title": "DiffRhythm Random Generation (No Prompt)"
     },

comfyui/workflows/text-to-music/diffrhythm-reference-based-v1.json

@@ -62,7 +62,7 @@
         false,
         "",
         "",
-        "[-1, 20], [60, -1]"
+        ""
       ],
       "title": "DiffRhythm Reference-Based Generation"
     },