fix: audio and text copy button enable/disable state

[phlpsong]

Update the audio button and text copy button disable state while query text is empty.

Please help to review this PR.

[github-actions]

Hello phlpsong, Thank you for your first PR contribution 🎉 phlpsong

[tisfeng]

感谢 PR，我试了一下，设置为 disable 状态后，感觉视觉效果不是很好，也可能是之前 enable 视觉看习惯了，因此这里我暂时还不想改。

如果你对这个项目感兴趣，可以帮忙看看其他的 issue。

[phlpsong]

@tisfeng thanks for your review comment.
What confused me here is I could do audio play or copy action while empty input(even though this has no effect).
I checked both light and dark appearance, it looks fine from my side.

[phlpsong]

@tisfeng Sure, if you don't want this change, I will close this PR later and check other issues if I can help.

[tisfeng]

这个暂时保持原样，你可以帮帮看其他 issue。