CA-143869: ZH-CN: Buttons are truncated on Workload Balancing Configuration

Fix the display issues of Chinese version XenCenter/WLB (Apologize for missing this fix within CA-142045):
When WLB Configuration Dialog size is changing,
1. OK and Cancel buttons are truncated,
2. OK and Cancel buttons do not keep at the bottom/right corner of the dialog.

Signed-off-by: Hui Zhang <hui.zhang@citrix.com>