fix: [254647/dock] device list might be shorten

[itsXuSt]

use resize to adjust the size of device list.

Log: as title.

Bug: https://pms.uniontech.com/bug-view-254647.html

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 在DeviceList类的showEvent函数中，调用setFixedHeight被替换为resize，可能会影响窗口的布局和响应式设计。
• 移除了showEvent的访问修饰符，如果其他类需要访问showEvent逻辑，可能会导致封装破坏。

是否建议立即修改:

• 是，应该评估resize和setFixedHeight的使用场景，确保它们的行为一致并且不会破坏现有的布局和响应式设计。
• 是，如果showEvent是类的重要逻辑，不应该轻易移除访问修饰符，以避免潜在的封装破坏。

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: itsXuSt, Johnson-zs

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[itsXuSt]

/merge