LibJS: Allow "approximately" results to differ in plural form

This is a normative change in the Intl.NumberFormat V3 spec. See:
https://github.com/tc39/proposal-intl-numberformat-v3/commit/08f599b

Note that this didn't seem to actually affect our implementation. The
Unicode spec states:

https://www.unicode.org/reports/tr35/tr35-53/tr35-numbers.html#Plural_Ranges
"If there is no value for a <start,end> pair, the default result is end"

Therefore, our implementation did not have the behavior noted by the
issue this normative change addressed:

    const pr = new Intl.PluralRules("en-US");
    pr.selectRange(1, 1); // Is "other", should be "one"

Our implementation already returned "one" here because there is no such
<start=one, end=one> value in the CLDR for en-US. Thus, we already
returned the end value of "one".

Userland/Libraries/LibJS/Runtime/Intl/RelativeTimeFormat.cpp

@@ -181,7 +181,7 @@ ThrowCompletionOr<Vector<PatternPartitionWithUnit>> partition_relative_time_patt
     auto plurality = MUST_OR_THROW_OOM(resolve_plural(vm, relative_time_format.plural_rules(), Value(value)));
 
     // 22. Let pattern be po.[[<pr>]].
-    auto pattern = patterns.find_if([&](auto& p) { return p.plurality == plurality; });
+    auto pattern = patterns.find_if([&](auto& p) { return p.plurality == plurality.plural_category; });
     if (pattern == patterns.end())
         return Vector<PatternPartitionWithUnit> {};