Fix vertical align of committer avatar rendered by email address (#21884)

Committer avatar rendered by `func AvatarByEmail` are not vertical align
as `func Avatar` does.

- Replace literals `ui avatar` and `ui avatar vm` with the constant
`DefaultAvatarClass`

Author: Xinyu Zhou

models/avatars/avatar.go

@@ -20,8 +20,12 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 )
 
-// DefaultAvatarPixelSize is the default size in pixels of a rendered avatar
-const DefaultAvatarPixelSize = 28
+const (
+	// DefaultAvatarClass is the default class of a rendered avatar
+	DefaultAvatarClass = "ui avatar vm"
+	// DefaultAvatarPixelSize is the default size in pixels of a rendered avatar
+	DefaultAvatarPixelSize = 28
+)
 
 // EmailHash represents a pre-generated hash map (mainly used by LibravatarURL, it queries email server's DNS records)
 type EmailHash struct {

modules/templates/helper.go

@@ -607,7 +607,7 @@ func AvatarHTML(src string, size int, class, name string) template.HTML {
 
 // Avatar renders user avatars. args: user, size (int), class (string)
 func Avatar(item interface{}, others ...interface{}) template.HTML {
-	size, class := gitea_html.ParseSizeAndClass(avatars.DefaultAvatarPixelSize, "ui avatar vm", others...)
+	size, class := gitea_html.ParseSizeAndClass(avatars.DefaultAvatarPixelSize, avatars.DefaultAvatarClass, others...)
 
 	switch t := item.(type) {
 	case *user_model.User:
@@ -638,7 +638,7 @@ func AvatarByAction(action *activities_model.Action, others ...interface{}) temp
 
 // RepoAvatar renders repo avatars. args: repo, size(int), class (string)
 func RepoAvatar(repo *repo_model.Repository, others ...interface{}) template.HTML {
-	size, class := gitea_html.ParseSizeAndClass(avatars.DefaultAvatarPixelSize, "ui avatar", others...)
+	size, class := gitea_html.ParseSizeAndClass(avatars.DefaultAvatarPixelSize, avatars.DefaultAvatarClass, others...)
 
 	src := repo.RelAvatarLink()
 	if src != "" {
@@ -649,7 +649,7 @@ func RepoAvatar(repo *repo_model.Repository, others ...interface{}) template.HTM
 
 // AvatarByEmail renders avatars by email address. args: email, name, size (int), class (string)
 func AvatarByEmail(email, name string, others ...interface{}) template.HTML {
-	size, class := gitea_html.ParseSizeAndClass(avatars.DefaultAvatarPixelSize, "ui avatar", others...)
+	size, class := gitea_html.ParseSizeAndClass(avatars.DefaultAvatarPixelSize, avatars.DefaultAvatarClass, others...)
 	src := avatars.GenerateEmailAvatarFastLink(email, size*setting.Avatar.RenderedSizeFactor)
 
 	if src != "" {