V13/bugfix/fix infinite editor stuck in create action 15945

[ealse]

Prerequisites

• I have added steps to test this contribution in the description below

If there's an existing issue for this PR then this fixes #15945

Description

Since the merge of issue #15032, a new item was created with every save action within an infinite editor.

The problem was that now the $scope.page.isNew was set to false instead of the $scope.isNew = false;
and that it was later overwritten by the wrong value.

[github-actions]

Hi there @ealse, thank you for this contribution! 👍

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[busrasengul]

Thank you @ealse The Core Collabs team will look into it soon 🎉