Add `clip_sample=False` to scheduler to make model compatible with DDIM.

Hey tuwonga 👋,

Your model repository seems to contain a stable diffusion checkpoint. We have noticed that your scheduler config currently does not correctly work with the [DDIMScheduler](https://huggingface.co/docs/diffusers/main/en/api/schedulers#diffusers.DDIMScheduler) because `clip_sample` is not set to False and will therefore [incorrectly default to True](https://github.com/huggingface/diffusers/blob/3ce6380d3a2ec5c3e3f4f48889d380d657b151bc/src/diffusers/schedulers/scheduling_ddim.py#L127).
The official stable diffusion checkpoints have `clip_sample=False` so that the scheduler config works will **all** schedulers, see: https://huggingface.co/stabilityai/stable-diffusion-2-1-base/blob/main/scheduler/scheduler_config.json#L7.

We strongly recommend that you merge this PR to make sure your model works correctly with DDIM.

Diffusingly,
Patrick.

scheduler/scheduler_config.json

@@ -4,6 +4,7 @@
   "beta_end": 0.012,
   "beta_schedule": "scaled_linear",
   "beta_start": 0.00085,
+  "clip_sample": false,
   "num_train_timesteps": 1000,
   "set_alpha_to_one": false,
   "skip_prk_steps": true,