Revert "Add instance_id param to chat completions"

This reverts commit 1d1e8ea.

Author: neubieser

openapi.yaml

@@ -5817,11 +5817,6 @@ components:
           maximum: 2
           nullable: true
           description: *completions_frequency_penalty_description
-        instance_id:
-          type: string
-          default: null
-          nullable: true
-          description: An unique identifier to a custom instance to execute the request. The requesting organization is required to have access to the instance.
         logit_bias:
           type: object
           x-oaiTypeLabel: map