Respect DEFAULT_ORG_MEMBER_VISIBLE setting when adding creator to org (#30013) (#30035)

Backport #30013 by @DrMaxNix

This PR adds `setting.Service.DefaultOrgMemberVisible` value to dataset
of user when the initial org creator is being added to the created org.

Fixes #30012.

Co-authored-by: DrMaxNix <mail@drmaxnix.de>
(cherry picked from commit e321b8a849087d736a96275d5960f9b1446c95ba)

models/organization/org.go

@@ -321,6 +321,7 @@ func CreateOrganization(org *Organization, owner *user_model.User) (err error) {
 	if err = db.Insert(ctx, &OrgUser{
 		UID:      owner.ID,
 		OrgID:    org.ID,
+		IsPublic: setting.Service.DefaultOrgMemberVisible,
 	}); err != nil {
 		return fmt.Errorf("insert org-user relation: %w", err)
 	}