Update docs for inference graph response code

[yuzisun]

What is changing? (Please include as many details as possible.)

Add dependency (soft/hard) field to the inference graph Step to determine whether to terminate the graph execution upon error responses.

How will this impact our users?

By default it maintains the current behavior as soft, if user specifies hard then it terminates at the current step upon error response.

In what release will this take happen (to the best of your knowledge)?

Ex. v0.11.1

Context

Link to associated PRs or issues from other repos here.

1. Inference Graph error response handling kserve#3039

Additional info