fix(gen-ai): remove max_tokens from external model verify request (opendatahub-io#7088)

max_tokens was hardcoded to 10 in the chat completions verification request,
which could cause failures with models that don't support the field.

Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: NickGagan

packages/gen-ai/bff/internal/integrations/externalmodels/client.go

@@ -21,9 +21,8 @@ import (
 
 // chatCompletionRequest represents an OpenAI-compatible chat completion request
 type chatCompletionRequest struct {
-	Model     string                  `json:"model"`
-	Messages  []chatCompletionMessage `json:"messages"`
-	MaxTokens int                     `json:"max_tokens,omitempty"`
+	Model    string                  `json:"model"`
+	Messages []chatCompletionMessage `json:"messages"`
 }
 
 // chatCompletionMessage represents a message in the chat completion request
@@ -235,7 +234,6 @@ func (c *ExternalModelsClient) VerifyModel(ctx context.Context, modelID string,
 			Messages: []chatCompletionMessage{
 				{Role: "user", Content: "test"},
 			},
-			MaxTokens: 10,
 		}
 		requestBody, err = json.Marshal(chatReq)
 		if err != nil {