fix(module:typography): edit area cannot get the content

[hsuanxyz]

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
[x] No

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #6369 (4c64a6a) into master (9d67d0b) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #6369      +/-   ##
==========================================
- Coverage   89.87%   89.85%   -0.02%     
==========================================
  Files         478      478              
  Lines       15275    15277       +2     
  Branches     2326     2326              
==========================================
- Hits        13728    13727       -1     
- Misses        930      931       +1     
- Partials      617      619       +2     

Impacted Files	Coverage Δ
...ponents/table/src/table/table-content.component.ts	100.00% <100.00%> (ø)
...s/table/src/table/table-inner-default.component.ts	100.00% <100.00%> (ø)
...ts/table/src/table/table-inner-scroll.component.ts	81.42% <100.00%> (ø)
components/table/src/table/tr-measure.component.ts	100.00% <100.00%> (ø)
components/typography/text-edit.component.ts	95.12% <100.00%> (-2.38%)	⬇️
components/typography/typography.component.ts	95.86% <100.00%> (+0.02%)	⬆️
components/tabs/tab-nav-bar.component.ts	82.39% <0.00%> (-0.71%)	⬇️

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