Refactor Find Sources and fix bug when view a user who belongs to an unactive auth source (#27798)

The steps to reproduce it.

First, create a new oauth2 source.
Then, a user login with this oauth2 source.
Disable the oauth2 source.
Visit users -> settings -> security, 500 will be displayed.
This is because this page only load active Oauth2 sources but not all
Oauth2 sources.

routers/web/user/setting/security/security.go

@@ -6,12 +6,14 @@ package security
 
 import (
 	"net/http"
+	"sort"
 
 	auth_model "code.gitea.io/gitea/models/auth"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/services/auth/source/oauth2"
 )
 
@@ -105,11 +107,31 @@ func loadSecurityData(ctx *context.Context) {
 	}
 	ctx.Data["AccountLinks"] = sources
 
-	orderedOAuth2Names, oauth2Providers, err := oauth2.GetActiveOAuth2Providers(ctx)
+	authSources, err := auth_model.FindSources(ctx, auth_model.FindSourcesOptions{
+		IsActive:  util.OptionalBoolNone,
+		LoginType: auth_model.OAuth2,
+	})
 	if err != nil {
-		ctx.ServerError("GetActiveOAuth2Providers", err)
+		ctx.ServerError("FindSources", err)
 		return
 	}
+
+	var orderedOAuth2Names []string
+	oauth2Providers := make(map[string]oauth2.Provider)
+	for _, source := range authSources {
+		provider, err := oauth2.CreateProviderFromSource(source)
+		if err != nil {
+			ctx.ServerError("CreateProviderFromSource", err)
+			return
+		}
+		oauth2Providers[source.Name] = provider
+		if source.IsActive {
+			orderedOAuth2Names = append(orderedOAuth2Names, source.Name)
+		}
+	}
+
+	sort.Strings(orderedOAuth2Names)
+
 	ctx.Data["OrderedOAuth2Names"] = orderedOAuth2Names
 	ctx.Data["OAuth2Providers"] = oauth2Providers