fix: 修复DLicenseDialog内存泄漏

[Whale107]

listModel没挂父对象也没有主动销毁

Log: 修复DLicenseDialog内存泄漏 Influence: DLicenseDialog

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: kegechen, Whale107

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/dtkwidget/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

[Whale107]

/merge

[deepin-bot[bot]]

This pr cannot be merged! (status: blocked)

[deepin-bot[bot]]

Doc Check bot :green_circle: Document Coverage Check Passed!

[Whale107]

/merge

[deepin-bot[bot]]

This pr cannot be merged! (status: blocked)

[Whale107]

/merge

[deepin-bot[bot]]

This pr cannot be merged! (status: blocked)

[xzl01]

/check obs

[deepin-bot[bot]]

Deepin Obs Bot Deepin redeliveried failed, need update or recreate pull request!!!