update the docstring at period parameter of ProbeSettings class (#34298)

* Update deployment_settings.py

`period` parameter description at `ProbeSettings class` is lack, so we can't check the what parameter means in [doc](https://learn.microsoft.com/en-us/python/api/azure-ai-ml/azure.ai.ml.entities.probesettings?view=azure-python).

I edited the docstring about `period` parameter and added description.

* Update sdk/ml/azure-ai-ml/azure/ai/ml/entities/_deployment/deployment_settings.py

---------

Co-authored-by: Anna Tisch <[email protected]>

Author: KazuOnuki

sdk/ml/azure-ai-ml/azure/ai/ml/entities/_deployment/deployment_settings.py

@@ -139,9 +139,9 @@ def __init__(
         :type success_threshold: int
         :param timeout: timeout in seconds, defaults to 2
         :type timeout: int
-        :param period: [description], defaults to 10
+        :param period: How often (in seconds) to perform the probe, defaults to 10
         :type period: int
-        :param initial_delay: How to to wait for the first probe, defaults to 10
+        :param initial_delay: How long (in seconds) to wait for the first probe, defaults to 10
         :type initial_delay: int
         """