fix(showcase): ui bug in rtl mode inside the doc site

[ParsaArvanehPA]

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?

[✔] 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?

Go to the current document site , follow these steps to reproduce the bug:

• click on the RTL button in the header
• start minimizing your window until you reach 993px
• when entering 992px, you will see that although the affix is gone, the main container doesn't take up the freed space

What is the new behavior?

The problem was with the specificity of CSS rules, with that corrected now when you reach the specified media query size, the main container will reduce its padding so that it can take up the space left behind by the said affix.

Does this PR introduce a breaking change?

[ ] Yes
[✔] No

Other information

[codecov]

Codecov Report

Merging #8063 (bfe0059) into master (7f7c155) will not change coverage.
The diff coverage is n/a.

❗ Current head bfe0059 differs from pull request most recent head 9f7c307. Consider uploading reports for the commit 9f7c307 to get more accurate results

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