fix(module:slider): the first disable is invalid

[OriginRing]

fix #7943

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: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[ ] No

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #7947 (bbfaf53) into master (538ef21) will decrease coverage by 0.04%.
The diff coverage is 100.00%.

❗ Current head bbfaf53 differs from pull request most recent head 6c88d51. Consider uploading reports for the commit 6c88d51 to get more accurate results

@@            Coverage Diff             @@
##           master    #7947      +/-   ##
==========================================
- Coverage   91.78%   91.74%   -0.04%     
==========================================
  Files         509      509              
  Lines       17444    17445       +1     
  Branches     2772     2683      -89     
==========================================
- Hits        16011    16005       -6     
- Misses       1134     1142       +8     
+ Partials      299      298       -1     

Impacted Files	Coverage Δ
components/date-picker/date-picker.component.ts	94.64% <100.00%> (+0.01%)	⬆️
components/slider/slider.component.ts	92.36% <100.00%> (ø)

... and 5 files with indirect coverage changes

[Nicoss54]

LGTM