It seems that UploadWizard unconditionally uses the php-intl Collator
Since intl isn't a hard dependency, because the default of wgCategoryCollation is still the simple 'uppercase' collator and since it's not listed as a requirement for UW in either composer.json nor in its documentation, i think we should correct this.
Introduced in change-id I35313fc3e41a4b26634f7c13bfb708bd04995100