fix(module:statistic): remove top-level redundant div element

[HyperLife1119]

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?

There is a layer of redundant div element under the nz-statistic element.

Issue Number: N/A

What is the new behavior?

Remove redundant div element.

Does this PR introduce a breaking change?

[x] Yes
[ ] No

DOM structure will change.

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #7659 (693af7e) into master (2d2fe33) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #7659      +/-   ##
==========================================
+ Coverage   92.01%   92.02%   +0.01%     
==========================================
  Files         502      502              
  Lines       16750    16750              
  Branches     2634     2634              
==========================================
+ Hits        15413    15415       +2     
+ Misses       1066     1065       -1     
+ Partials      271      270       -1     

Impacted Files	Coverage Δ
components/statistic/statistic.component.ts	100.00% <ø> (ø)
components/tabs/tab-nav-bar.component.ts	87.94% <0.00%> (+0.70%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.