Reset all VT attributes for PromptText if it contains VT sequences

[daxian-dbw]

PR Summary

Fix #1542
Reset all VT attributes for PromptText if it contains VT sequences.
If the text doesn't contain VT sequences, we leave it unchanged, so that when rendering we can apply the default error color as expected.

After the fix, the color doesn't leak in the formatted output:

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure you've added one or more new tests
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed at PowerShell-Docs
    • Doc Issue filed:

Microsoft Reviewers: Open in CodeFlow

[iSazonov]

Will this fix PowerShell/PowerShell#11267 too?

[daxian-dbw]

@iSazonov No this doesn't.