fix: the recorder taskbar incorrect foreground-color

[add-uos]

Log: fix the recorder taskbar incorrect foreground-color Bug: https://pms.uniontech.com/bug-view-268895.html

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 在QPalette的设置中，应该检查DGuiApplicationHelper::instance()->themeType()是否存在，以避免潜在的空指针异常。
• 颜色值的比较应该使用==而不是!=，以避免可能的逻辑错误。
• 新增代码块中，对DGuiApplicationHelper::instance()->themeType()的检查应该放在else分支之前，以确保在主题类型为LightType时正确设置颜色。

是否建议立即修改:

• 是

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: add-uos, lzwind

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](https://github.com/linuxdeepin/deepin-screen-recorder/blob/master/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

[add-uos]

/merge