Fix org contact email not clearable once set (#36975)

When the email field was submitted as empty in org settings (web and
API), the previous guard `if form.Email != ""` silently skipped the
update, making it impossible to remove a contact email after it was set.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/api/v1/org/org.go

@@ -5,6 +5,7 @@
 package org
 
 import (
+	"errors"
 	"net/http"
 
 	activities_model "code.gitea.io/gitea/models/activities"
@@ -14,6 +15,7 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/optional"
 	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/routers/api/v1/user"
 	"code.gitea.io/gitea/routers/api/v1/utils"
@@ -379,19 +381,21 @@ func Edit(ctx *context.APIContext) {
 
 	form := web.GetForm(ctx).(*api.EditOrgOption)
 
-	if form.Email != "" {
-		if err := user_service.ReplacePrimaryEmailAddress(ctx, ctx.Org.Organization.AsUser(), form.Email); err != nil {
-			ctx.APIErrorInternal(err)
+	if err := org.UpdateOrgEmailAddress(ctx, ctx.Org.Organization, form.Email); err != nil {
+		if errors.Is(err, util.ErrInvalidArgument) {
+			ctx.APIError(http.StatusUnprocessableEntity, err)
 			return
 		}
+		ctx.APIErrorInternal(err)
+		return
 	}
 
 	opts := &user_service.UpdateOptions{
-		FullName:                  optional.Some(form.FullName),
-		Description:               optional.Some(form.Description),
-		Website:                   optional.Some(form.Website),
-		Location:                  optional.Some(form.Location),
-		Visibility:                optional.FromMapLookup(api.VisibilityModes, form.Visibility),
+		FullName:                  optional.FromPtr(form.FullName),
+		Description:               optional.FromPtr(form.Description),
+		Website:                   optional.FromPtr(form.Website),
+		Location:                  optional.FromPtr(form.Location),
+		Visibility:                optional.FromMapLookup(api.VisibilityModes, optional.FromPtr(form.Visibility).Value()),
 		RepoAdminChangeTeamAccess: optional.FromPtr(form.RepoAdminChangeTeamAccess),
 	}
 	if err := user_service.UpdateUser(ctx, ctx.Org.Organization.AsUser(), opts); err != nil {