no-jira: remove circular dependency in translation files en after i18n server merge

src/main/java/org/olat/course/member/_i18n/LocalStrings_en.properties

@@ -15,7 +15,7 @@ edit.member.groups=Group membership
 edit.member.groups.desc=Add user to the groups below by selecting the appropriate checkboxes.
 edit.member.repo.desc=Add user to the course as\:
 edit.member.title=Member right for the course "{0}"
-error.atleastone=At least one owner is required in a course.
+error.atleastone=$org.olat.group.ui.main\:error.atleastone
 group.add=Add group
 group.create=Create group
 group.remove=$org.olat.group.ui.edit\:resource.remove

src/main/java/org/olat/group/ui/main/_i18n/LocalStrings_en.properties

@@ -39,7 +39,7 @@ edit.member=Edit membership
 edit.member.groups=Group memberships
 edit.member.title=Member rights course {0}
 email.group=Send E-mail
-error.atleastone=$org.olat.course.member\:error.atleastone
+error.atleastone=At least one owner is required in a course.
 group.access.success=Access to group is successful
 group.used.in.course=This group is used in the following courses\:
 hide=Hide information