Use user.FullName in Oauth2 id_token response

This makes `/login/oauth/authorize` behave the same way as the
`/login/oauth/userinfo` endpoint.

routers/web/auth/oauth2_provider.go

@@ -98,7 +98,7 @@ func InfoOAuth(ctx *context.Context) {
 
 	response := &userInfoResponse{
 		Sub:      fmt.Sprint(ctx.Doer.ID),
-		Name:     ctx.Doer.FullName,
+		Name:     ctx.Doer.DisplayName(),
 		Username: ctx.Doer.Name,
 		Email:    ctx.Doer.Email,
 		Picture:  ctx.Doer.AvatarLink(ctx),

routers/web/auth/oauth_test.go

@@ -66,25 +66,7 @@ func TestNewAccessTokenResponse_OIDCToken(t *testing.T) {
 
 	// Scopes: openid profile email
 	oidcToken = createAndParseToken(t, grants[0])
-	assert.Equal(t, user.Name, oidcToken.Name)
-	assert.Equal(t, user.Name, oidcToken.PreferredUsername)
-	assert.Equal(t, user.HTMLURL(), oidcToken.Profile)
-	assert.Equal(t, user.AvatarLink(db.DefaultContext), oidcToken.Picture)
-	assert.Equal(t, user.Website, oidcToken.Website)
-	assert.Equal(t, user.UpdatedUnix, oidcToken.UpdatedAt)
-	assert.Equal(t, user.Email, oidcToken.Email)
-	assert.Equal(t, user.IsActive, oidcToken.EmailVerified)
-
-	// set DefaultShowFullName to true
-	oldDefaultShowFullName := setting.UI.DefaultShowFullName
-	setting.UI.DefaultShowFullName = true
-	defer func() {
-		setting.UI.DefaultShowFullName = oldDefaultShowFullName
-	}()
-
-	// Scopes: openid profile email
-	oidcToken = createAndParseToken(t, grants[0])
-	assert.Equal(t, user.FullName, oidcToken.Name)
+	assert.Equal(t, user.DisplayName(), oidcToken.Name)
 	assert.Equal(t, user.Name, oidcToken.PreferredUsername)
 	assert.Equal(t, user.HTMLURL(), oidcToken.Profile)
 	assert.Equal(t, user.AvatarLink(db.DefaultContext), oidcToken.Picture)

services/oauth2_provider/access_token.go

@@ -148,7 +148,7 @@ func NewAccessTokenResponse(ctx context.Context, grant *auth.OAuth2Grant, server
 			Nonce: grant.Nonce,
 		}
 		if grant.ScopeContains("profile") {
-			idToken.Name = user.GetDisplayName()
+			idToken.Name = user.DisplayName()
 			idToken.PreferredUsername = user.Name
 			idToken.Profile = user.HTMLURL()
 			idToken.Picture = user.AvatarLink(ctx)