applets/taskmanager: Workaround for QTBUG-102811

When the size of ScrollView depends on its delegate items and `reuseItems`
is set to true, the program is prone to crash.

Although delayed binding on `Layout.minimumWidth` mitigates the crash,
there are still some related crash reports.

This adds a workaround for QTBUG-102811 to fix the potential crash. To
reproduce the crash, open 20 Konsole windows and 2 windows of other
program, set `delayed: false` in `Binding on Layout.minimumWidth` in the
origin code, and move mouse between the two grouped tasks in the task
manager.

BUG: 452660