fix: prevent MC791596 banner migration for pages with no header

[nicolaor]

fix: prevent MC791596 banner migration for pages with no header

When saving a page with PageHeaderType.None, the legacy NoHeader() HTML
was written to LayoutWebpartsContent. SharePoint's MC791596 migration
detects this HTML on first browser open and injects a full-width Banner
web part into CanvasContent1, causing an unwanted header to appear on
pages created from the template.

Write string.Empty instead of NoHeader() to avoid triggering the migration.
Also skip the entire header persistence block for Home layout pages, which
do not support a banner header.

This might also fix #1718

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 81.15942% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.25%. Comparing base (63545f3) to head (416932a).
⚠️ Report is 2907 commits behind head on dev.

Files with missing lines	Patch %	Lines
...rePoint/Core/Internal/LegacyPrincipalManagement.cs	80.55%	4 Missing and 3 partials ⚠️
...k/PnP.Core/Model/SharePoint/Pages/Internal/Page.cs	81.81%	4 Missing and 2 partials ⚠️
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Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1758      +/-   ##
==========================================
- Coverage   82.42%   81.25%   -1.17%     
==========================================
  Files         416      637     +221     
  Lines       28590    45388   +16798     
  Branches        0     4778    +4778     
==========================================
+ Hits        23565    36880   +13315     
- Misses       5025     7099    +2074     
- Partials        0     1409    +1409     

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[Adam-it]

Thanks for dropping a PR and helping us out. We will try to review it ASAP.
Also, in future please always ensure you first open up an issue, let use discuss and clarify on the solution first, and then open a PR once we agree on the change 👍

[nicolaor]

@Adam-it sorry for that. I had already implemented this in our fork, so when I saw issue #1718 I thought it might be a good idea to just share the code we are using, without wasting too much time creating a separate issue for it ;-)

[Adam-it]

@Adam-it sorry for that. I had already implemented this in our fork, so when I saw issue #1718 I thought it might be a good idea to just share the code we are using, without wasting too much time creating a separate issue for it ;-)

Gotcha, thanks for sharing 👍.
Will try to go over it and try to merge it ASAP so other folks may use the best from the PnP package as well 🤩.

If you have more improvements/fixes done locally, please do share them as well 👍
Sharing is caring