[usecase-wrt]update script click button event

Impacted TCs num(approved): New 0, update 2, deleted 0
Unit test platform: [tizen]
Unit test result summary: Pass 1, Fail 0, Blocked 1
Block reason: zoom pic no device to check.
Merge pull request #733 from linshen/wrt-usecase-tizen-alert

[usecase-wrt]update script click button event