dev/core#5449 set NOINDEX on non-public event registration pages

[eileenmcnaughton]

alternative to #31074

[civibot]

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[civibot]

The issue associated with the Pull Request can be viewed at https://lab.civicrm.org/dev/core/-/issues/5449

[magnolia61]

I love this solution. Will test tommorrow (NL time).

While we're at it maybe we should think of all places that should receive the noindex for public facing pages that are configured as non-public

[colemanw]

@magnolia61 have you had a chance to test this?

[mattwire]

Merging as seems like a good generic improvement. @magnolia61 Please test further and continue to iterate.