Fix noise scheduler api for ldm inference (Project-MONAI#1419)

Fixes Project-MONAI#1418  .

### Description

Update the argument for monai generative >=0.22

### Checks
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Signed-off-by: Mingxin <[email protected]>

Author: mingxin-zheng

generative/2d_ldm/inference.py

@@ -78,7 +78,7 @@ def main():
 
     scheduler = DDPMScheduler(
         num_train_timesteps=args.NoiseScheduler["num_train_timesteps"],
-        beta_schedule="scaled_linear",
+        schedule="scaled_linear_beta",
         beta_start=args.NoiseScheduler["beta_start"],
         beta_end=args.NoiseScheduler["beta_end"],
     )

generative/3d_ldm/inference.py

@@ -78,7 +78,7 @@ def main():
 
     scheduler = DDPMScheduler(
         num_train_timesteps=args.NoiseScheduler["num_train_timesteps"],
-        beta_schedule="scaled_linear",
+        schedule="scaled_linear_beta",
         beta_start=args.NoiseScheduler["beta_start"],
         beta_end=args.NoiseScheduler["beta_end"],
     )