Backport System.Globalization.Extensions.Tests for icu 74/unicode 15.1

[richlander]

We made fixes last year that need to be backported to release/8.0. These probably should have been backported at the time of the earlier PR. Not a criticism but just an observation. This type of change typically affects all the distros in a staggered fashion and affects our LTS versions.

Related:

• Fix System.Globalization.Extensions.Tests for icu 74/unicode 15.1 #105282
• release/8.0-staging -- Update Alpine and Fedora versions #110492

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[richlander]

FYI @omajid

[tarekgh]

Created #110499 and will close this one.