[fix] correctly strip data suffix at root page

[dummdidumm]

Fixes #7434
Was accidentally introduced through #7419

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Latest commit: 8e82063

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[dominikg]

looks good. is it possible to add a regression test to this. feels pretty critical to ensure that invalidation et al is working correctly

[dummdidumm]

yeah it's on my todo-list for later, but first want to get the fix out