[gemini] fixed the gemini checkpoint io

[FrankLeeeee]

📌 Checklist before creating the PR

• I have created an issue for this PR for traceability
• The title follows the standard format: [doc/gemini/tensor/...]: A concise description
• I have added relevant tags if possible for us to better distinguish different PRs

🚨 Issue number

Link this PR to your issue with words like fixed to automatically close the linked issue upon merge

e.g. fixed #1234, closed #1234, resolved #1234

Fixed #3933

📝 What does this PR do?

Summarize your work here.
if you have any plots/diagrams/screenshots/tables, please attach them here.

This PR fixed the logic to handle the parameter shard block in the Gemini's model state dict to avoid empty checkpoint shard.

💥 Checklist before requesting a review

• I have linked my PR to an issue (instruction)
• My issue clearly describes the problem/feature/proposal, with diagrams/charts/table/code if possible
• I have performed a self-review of my code
• I have added thorough tests.
• I have added docstrings for all the functions/methods I implemented

⭐️ Do you enjoy contributing to Colossal-AI?

• 🌝 Yes, I do.
• 🌚 No, I don't.

Tell us more if you don't enjoy contributing to Colossal-AI.

[github-actions]

The code coverage for the changed files is 86%.

Click me to view the complete report

Name                                                      Stmts   Miss  Cover
-----------------------------------------------------------------------------
colossalai/booster/plugin/gemini_plugin.py                  110      9    92%
colossalai/checkpoint_io/index_file.py                       65     16    75%
colossalai/device/device_mesh.py                            143      6    96%
colossalai/lazy/lazy_init.py                                299     40    87%
colossalai/tensor/comm_spec.py                              253     93    63%
colossalai/tensor/d_tensor/__init__.py                        3      0   100%
colossalai/tensor/d_tensor/comm_spec.py                     151     35    77%
colossalai/tensor/d_tensor/d_tensor.py                       67     11    84%
colossalai/tensor/d_tensor/layout.py                         38      1    97%
colossalai/tensor/d_tensor/layout_converter.py              202     13    94%
colossalai/tensor/d_tensor/sharding_spec.py                 105     14    87%
colossalai/zero/gemini/gemini_ddp.py                        402     67    83%
tests/test_device/test_device_mesh.py                        11      1    91%
tests/test_device/test_init_logical_pg.py                    27      1    96%
tests/test_lazy/lazy_init_utils.py                           71     14    80%
tests/test_lazy/test_distribute.py                           73      3    96%
tests/test_tensor/test_dtensor/test_comm_spec.py             81      1    99%
tests/test_tensor/test_dtensor/test_dtensor.py               67      5    93%
tests/test_tensor/test_dtensor/test_layout_converter.py      91      1    99%
tests/test_tensor/test_shape_consistency.py                  50      2    96%
tests/test_tensor/test_sharded_linear.py                    130      1    99%
tests/test_tensor/test_sharding_spec.py                      13      1    92%
-----------------------------------------------------------------------------
TOTAL                                                      2452    335    86%