[Snyk] Upgrade @umbraco-cms/backoffice from 15.3.1 to 15.4.2#140

jcdcdev merged 1 commit intodev/v15jcdcdev/Umbraco.Community.BackOfficeOrganiser:dev/v15from

snyk-upgrade-029a7906aa7555719f7dccb4aaeaca41jcdcdev/Umbraco.Community.BackOfficeOrganiser:snyk-upgrade-029a7906aa7555719f7dccb4aaeaca41Copy head branch name to clipboard