enable SizeMode support by default.
user can set environment `D_DTK_SIZEMODE` to set
SizeMode support.
application can set SizeMode by `setSizeMode` explicitly.
Log: 支持紧凑模式切换
Task: https://pms.uniontech.com/task-view-227385.html
Influence: none
Change-Id: I2eefe254f9bbf380d9ab133c4eb0caa979ed1356