[Fix] Sync seed for dist sampler

[MeowZheng]

as title
ref: open-mmlab/mmdetection#7432 and open-mmlab/mmdetection#7440

[codecov]

Codecov Report

Merging #110 (9a30173) into master (413553e) will increase coverage by 0.18%.
The diff coverage is 62.50%.

@@            Coverage Diff             @@
##           master     #110      +/-   ##
==========================================
+ Coverage   68.45%   68.63%   +0.18%     
==========================================
  Files          89       91       +2     
  Lines        4999     5019      +20     
  Branches      713      716       +3     
==========================================
+ Hits         3422     3445      +23     
+ Misses       1468     1463       -5     
- Partials      109      111       +2     

Flag	Coverage Δ
unittests	68.63% <62.50%> (+0.18%)	⬆️

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Impacted Files	Coverage Δ
mmflow/datasets/builder.py	87.50% <ø> (ø)
mmflow/core/utils/dist_utils.py	56.25% <56.25%> (ø)
mmflow/datasets/samplers/distributed_sampler.py	53.01% <66.66%> (+1.16%)	⬆️
mmflow/core/utils/__init__.py	100.00% <100.00%> (ø)
mmflow/datasets/pipelines/transforms.py	79.83% <0.00%> (+1.66%)	⬆️

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