fix(module:checkbox): fix trigger twitce in safari

[SangKa]

Close #254

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: #254

What is the new behavior?

make nzChecked @input only and only let the click on the host to control the check status.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[coveralls]

Coverage increased (+0.004%) to 40.999% when pulling 47c0fd2 on SangKa:fix-254 into 2f031ce on NG-ZORRO:master.