ICU4X RelativeDatetime format not respecting Latn numbering system for locale "bn"

[sven-oly]

[sven-oly]

See failing tests here: https://unicode-org.github.io/conformance/rust/icu77/rdt_fmt/verifier_test_report.html.

All failing tests are for locale "bn" and requested numbering system "latn".

[sven-oly]

Note that the ICU4X executor explicitly flags numbering system != "latn" as "unsupported". Should these failures be changed to "unsupported", too?

[sffc]

Should be fixed in unicode-org/icu4x#6928

[sven-oly]

The ICU4X fix should resolve all test failures and unsupported issues in this component of this platform!