fix line end with new-line in some backend (#474)

* fix line end with new-line in some backend

In backend with golang (like https://github.com/sashabaranov/go-openai), the responseText always has '\n'.

* feat: 补全遗漏

---------

Co-authored-by: ChenZhaoYu <790348264@qq.com>

src/views/chat/index.vue

@@ -115,7 +115,7 @@ async function onConversation() {
           const xhr = event.target
           const { responseText } = xhr
           // Always process the final line
-          const lastIndex = responseText.lastIndexOf('\n')
+          const lastIndex = responseText.lastIndexOf('\n', responseText.length - 2)
           let chunk = responseText
           if (lastIndex !== -1)
             chunk = responseText.substring(lastIndex)
@@ -245,7 +245,7 @@ async function onRegenerate(index: number) {
           const xhr = event.target
           const { responseText } = xhr
           // Always process the final line
-          const lastIndex = responseText.lastIndexOf('\n')
+          const lastIndex = responseText.lastIndexOf('\n', responseText.length - 2)
           let chunk = responseText
           if (lastIndex !== -1)
             chunk = responseText.substring(lastIndex)