Invoke-PnPSiteTemplate: Double Header when importing pages with vertical section

[till-llit]

this is a follow up to #1058

even with the fix in #1066 and #1102 from @czullu we see issues in specific page layouts - especially when using a vertical section.

repro:

create a page with a vertical section and a page title:

use the latest pnp Powershell nightly: 2.99.154
execute export-pnppage BANNER-TITLE.aspx -out BANNER-TITLE.aspx.xml to create an xml export

execute Invoke-PnPSiteTemplate -path .\BANNER-TITLE.aspx.xml to import the page

the page is now created with 2 banner webparts, one is a default title without the layout we had and the other one is a banner webpart in Section 1 with our custom layout: