Automated cherry pick of #965: fix: page-container Card style bug

[erda-bot]

Cherry pick of #965 on release/1.2.

Squashed commit message:

commit 07d6456c95f0bfbc53659b93b9d4c44c9ef2d077
Author: hujiahao-hjh <[email protected]>
Date:   Tue Aug 17 12:32:50 2021 +0800

    fix: page-container Card style bug (#965)

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What this PR does / why we need it:

fix page-container Card style bug.

Does this PR introduce a user interface change?

✅ Yes(screenshot is required)

->

ChangeLog

Language	Changelog
🇺🇸 English	Fixed an API design bug that did not display empty page icon when the page had no branches.
🇨🇳 中文	解决了api设计页面无分支时不显示空页面图标的bug。

Does this PR need be patched to older version?

✅ Yes(version is required)
release/1.2

Which issue(s) this PR fixes:

Fixes # page-container Card style bug