fix(fern/apis/api/openapi.json): Update model and provider field types and values

This commit makes changes to the `openapi.json` file in the `fern/apis/api` directory. Specifically, it updates the schema of the `model` and `provider` fields. The `model` field type is changed from `string` to `object`, and an enum of possible model values is added, including various versions of "Gemini" and "Google". The `provider` field now has an enum specifying "google" as the only possible value.

Author: fern-api[bot]

fern/apis/api/openapi.json

@@ -19492,11 +19492,27 @@
           "provider": {
             "type": "string",
             "description": "The provider of the knowledge base",
+            "enum": [
+              "google"
+            ],
             "example": "google"
           },
           "model": {
-            "type": "string",
+            "type": "object",
             "description": "The model to use for the knowledge base",
+            "enum": [
+              "gemini-2.0-flash-thinking-exp",
+              "gemini-2.0-pro-exp-02-05",
+              "gemini-2.0-flash",
+              "gemini-2.0-flash-lite-preview-02-05",
+              "gemini-2.0-flash-exp",
+              "gemini-2.0-flash-realtime-exp",
+              "gemini-1.5-flash",
+              "gemini-1.5-flash-002",
+              "gemini-1.5-pro",
+              "gemini-1.5-pro-002",
+              "gemini-1.0-pro"
+            ],
             "example": "gemini-1.5-flash"
           },
           "description": {