fix(module: accordion): fix accordion support template and add support innerHtml

[Guoyuanqiang]

…t innerHtml

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-mobile/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
[x] 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

[Guoyuanqiang]

close #306

[codecov]

Codecov Report

Merging #307 into master will decrease coverage by 0.25%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #307      +/-   ##
==========================================
- Coverage    89.9%   89.64%   -0.26%     
==========================================
  Files         228      229       +1     
  Lines        6832     6865      +33     
  Branches      551      561      +10     
==========================================
+ Hits         6142     6154      +12     
- Misses        526      547      +21     
  Partials      164      164

Impacted Files	Coverage Δ
...rdion/accordion-group/accordion-group.component.ts	86.84% <100%> (+0.73%)	⬆️
components/accordion/accordion.module.ts	100% <100%> (ø)	⬆️
components/core/util/check.ts	30% <0%> (ø)

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