Support for Custom URI Schemes in OAuth2 Redirect URIs (#37356)

Fix #34349

By the way, remove `(ctx *APIContext) HasAPIError() ` and `(ctx
*APIContext) GetErrMsg()` because they do nothing, the error handling
has been done in API's middeware

The existing OAuth2 tests were not quite right, refactored them together

modules/validation/binding.go

@@ -13,7 +13,6 @@ import (
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/glob"
 	"code.gitea.io/gitea/modules/json"
-	"code.gitea.io/gitea/modules/util"
 
 	"gitea.com/go-chi/binding"
 )
@@ -51,7 +50,6 @@ func (j jsonProvider) NewEncoder(writer io.Writer) binding.JSONEncoder {
 func AddBindingRules() {
 	binding.JSONProvider = jsonProvider{}
 	addGitRefNameBindingRule()
-	addValidURLListBindingRule()
 	addValidURLBindingRule()
 	addValidSiteURLBindingRule()
 	addGlobPatternRule()
@@ -80,33 +78,6 @@ func addGitRefNameBindingRule() {
 	})
 }
 
-func addValidURLListBindingRule() {
-	// URL validation rule
-	binding.AddRule(&binding.Rule{
-		IsMatch: func(rule string) bool {
-			return rule == "ValidUrlList"
-		},
-		IsValid: func(errs binding.Errors, name string, val any) (bool, binding.Errors) {
-			str := fmt.Sprintf("%v", val)
-			if len(str) == 0 {
-				errs.Add([]string{name}, binding.ERR_URL, "Url")
-				return false, errs
-			}
-
-			ok := true
-			urls := util.SplitTrimSpace(str, "\n")
-			for _, u := range urls {
-				if !IsValidURL(u) {
-					ok = false
-					errs.Add([]string{name}, binding.ERR_URL, u)
-				}
-			}
-
-			return ok, errs
-		},
-	})
-}
-
 func addValidURLBindingRule() {
 	// URL validation rule
 	binding.AddRule(&binding.Rule{