fix(NcRichText): render invalid relative markdown links as external

[Antreesy]

☑️ Resolves

fix(autolink): fix rendering of nested markdown link with

• with autolink + useMarkdown props [href2](href1) syntax is rendered as <a href1><a href2>href2</a></a> instead of href2 being a plain text

🏚️ Before	🏡 After

fix(NcRichText)!: render all non-resolved links as external

• this covers:
  • external links (as before)
  • internal absolute links, but from another app (as before)
  • and internal relative links, that do not have a router match for current app (new)
    • possibly a breaking change?
    • this is likely an invalid user input, it shouldn't unload the page and destroy an app

🚧 Tasks

• Consult other teams for using of relative links, whether it's breaking for them

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 2️⃣ Backport to stable8 for maintained Vue 2 version or not applicable

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 54.08%. Comparing base (08100af) to head (6b21c2b).
⚠️ Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
src/components/NcRichText/autolink.ts	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8397      +/-   ##
==========================================
- Coverage   54.09%   54.08%   -0.01%     
==========================================
  Files         104      105       +1     
  Lines        3398     3400       +2     
  Branches      989      990       +1     
==========================================
+ Hits         1838     1839       +1     
- Misses       1321     1322       +1     
  Partials      239      239              

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