fix: changeoptional field to pointer type (#1907)

* fix:修复在渠道配置中设置模型重定向时，temperature为0被忽略的问题

* fix: set optional fields to pointer type

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Co-authored-by: JustSong <songquanpeng@foxmail.com>

relay/adaptor/aws/llama3/model.go

@@ -4,10 +4,10 @@ package aws
 //
 // https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-meta.html
 type Request struct {
-	Prompt      string  `json:"prompt"`
-	MaxGenLen   int     `json:"max_gen_len,omitempty"`
-	Temperature float64 `json:"temperature,omitempty"`
-	TopP        float64 `json:"top_p,omitempty"`
+	Prompt      string   `json:"prompt"`
+	MaxGenLen   int      `json:"max_gen_len,omitempty"`
+	Temperature *float64 `json:"temperature,omitempty"`
+	TopP        *float64 `json:"top_p,omitempty"`
 }
 
 // Response is the response from AWS Llama3