fix: fix the bug with render class ant-upload-drag-container in dom

[Dmytro-Lukashenko]

Hello!
I have searched the issues of this repository and believe that this is not a duplicate.

Version
3.2.16

Environment
ant-design-vue 3.2.16;
vue-3.2.0

Reproduction link
https://codesandbox.io/s/a-upload-dragger-class-issue-nzg0v9?file=/src/App.vue

Steps to reproduce
There is an incorrect rendering of the class "ant-upload-drag-container" in DOM. If we use an empty tag <a-upload-dragger></a-upload-dragger>, the empty <div> with class "[object Object]-drag-container" renders in DOM.

This happens because of an error in string 397 of the Upload.tsx file.
<div class={${prefixCls}-drag-container}>{slots.default?.()}</div>
prefixCls - ComputedRef, not a string.
To fix this issue, we can modify the code to access the string value of the prefixCls object - prefixCls.value
My suggestion:
<div class={${prefixCls.value}-drag-container}>{slots.default?.()}</div>

What is expected?
The class "ant-upload-dragger-container" should be rendered in DOM

What is actually happening?
The class "[object Object]-drag-container" renders in DOM

[github-actions]

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