DistributedWeightedRandomSampler remove `shuffle=False` option

[wyli]

Describe the bug

MONAI/monai/data/samplers.py

Line 98 in 4cd717c

shuffle: bool = True,

the random sampler will always generate 'shuffled' outputs, the shuffle=False option is not valid and should be removed

[AmirAflak]

Would like to take this.