MonaiAlgo: fix logging in multi-gpu training (#5355)

Signed-off-by: Holger Roth <[email protected]>

Fixes #5354.

### Description

Previous output:
```
Current output:
2022-10-18 12:45:59,679 - MonaiAlgo - INFO - Using multi-gpu training on rank 1 (available devices: 2)
2022-10-18 12:45:59,681 - MonaiAlgo - INFO - Using multi-gpu training on rank 0 (available devices: 2)
2022-10-18 12:49:48,790 - ignite.engine.engine.SupervisedTrainer - INFO - Got new best metric of train_accuracy: 0.802879669048168
2022-10-18 12:49:48,790 - ignite.engine.engine.SupervisedTrainer - INFO - Got new best metric of train_accuracy: 0.802879669048168
2022-10-18 12:49:56,579 - ignite.engine.engine.SupervisedEvaluator - INFO - Got new best metric of val_mean_dice: 0.1470419466495514
2022-10-18 12:49:56,579 - ignite.engine.engine.SupervisedEvaluator - INFO - Got new best metric of val_mean_dice: 0.1470419466495514
```
Output after fix:
```
2022-10-18 12:51:05,400 - MonaiAlgo - INFO - Using multi-gpu training on rank 0 (available devices: 2)
2022-10-18 12:51:05,410 - MonaiAlgo - INFO - Using multi-gpu training on rank 1 (available devices: 2)
2022-10-18 12:53:09,889 - ignite.engine.engine.SupervisedTrainer - INFO - Got new best metric of train_accuracy: 0.6750877521656178
2022-10-18 12:53:25,170 - ignite.engine.engine.SupervisedEvaluator - INFO - Got new best metric of val_mean_dice: 0.06980131566524506
```

### Types of changes
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).
- [x] Breaking change (fix or new feature that would cause existing
functionality to change).
- [ ] New tests added to cover the changes.
- [ ] Integration tests passed locally by running `./runtests.sh -f -u
--net --coverage`.
- [ ] Quick tests passed locally by running `./runtests.sh --quick
--unittests --disttests`.
- [ ] In-line docstrings updated.
- [ ] Documentation updated, tested `make html` command in the `docs/`
folder.

Signed-off-by: Holger Roth <[email protected]>

monai/fl/client/monai_algo.py

@@ -494,6 +494,11 @@ def initialize(self, extra=None):
             BundleKeys.DATASET_DIR, default=ConfigItem(None, BundleKeys.DATASET_DIR)
         )
 
+        if self.multi_gpu:
+            if self.rank > 0 and self.trainer:
+                self.trainer.logger.setLevel(logging.WARNING)
+            if self.rank > 0 and self.evaluator:
+                self.evaluator.logger.setLevel(logging.WARNING)
         self.logger.info(f"Initialized {self.client_name}.")
 
     def train(self, data: ExchangeObject, extra=None):