fix: can't set transparent for Menu's background

[18202781743]

Menu's background always fill a color even it's transparent. in somecase we need fill background by caller.

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 在新增的条件判断中，检查了color.color().alpha() != 0，这是一个好的做法，可以避免在背景色为完全透明时仍然绘制菜单项背景。

是否建议立即修改:

• 否，当前提交的修改是合理的，没有发现需要立即修改的问题。但是，建议进行以下几点改进：
  • 确保新增的条件判断color.color().alpha() != 0的逻辑正确，并且与整体代码库的逻辑一致。
  • 如果代码库中有针对透明背景的菜单项背景绘制逻辑，确保它们不会互相冲突，并且与当前的修改协同工作。
  • 添加必要的注释，解释为什么需要检查alpha()不为0，以便其他开发者理解这一变更的背景。
  • 如果代码库中有单元测试，确保它们能够覆盖到这一更改的情况，并且测试通过。

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: 18202781743, zccrs

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• debian/deepin/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment