LibUnicode+LibJS: Store locale keyword values as a single string

Previously, LibUnicode would store the values of a keyword as a Vector.
For example, the locale "en-u-ca-abc-def" would have its keyword "ca"
stored as {"abc, "def"}. Then, canonicalization would occur on each of
the elements in that Vector.

This is incorrect because, for example, the keyword value "true" should
only be dropped if that is the entire value. That is, the canonical form
of "en-u-kb-true" is "en-u-kb", but "en-u-kb-abc-true" does not change
for canonicalization. However, we would canonicalize that locale as
"en-u-kb-abc".

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

@@ -6,7 +6,6 @@
 
 #include <AK/Optional.h>
 #include <AK/String.h>
-#include <AK/StringBuilder.h>
 #include <LibJS/Runtime/AbstractOperations.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Intl/AbstractOperations.h>
@@ -193,9 +192,7 @@ static LocaleAndKeys apply_unicode_extension_to_tag(StringView tag, LocaleAndKey
             entry = &(*it);
 
             // ii. Let value be entry.[[Value]].
-            StringBuilder builder;
-            builder.join('-', entry->types);
-            value = builder.build();
+            value = entry->value;
         }
         // c. Else,
         //     i. Let entry be empty.
@@ -213,12 +210,12 @@ static LocaleAndKeys apply_unicode_extension_to_tag(StringView tag, LocaleAndKey
             // iii. If entry is not empty, then
             if (entry != nullptr) {
                 // 1. Set entry.[[Value]] to value.
-                entry->types = value->split('-');
+                entry->value = *value;
             }
             // iv. Else,
             else {
                 // 1. Append the Record { [[Key]]: key, [[Value]]: value } to keywords.
-                keywords.append({ key, value->split('-') });
+                keywords.append({ key, *value });
             }
         }