fix(api): allow bots with pending password changes (#39551)

Allow bot accounts to use the API when a legacy password-change flag is
set, since bots cannot complete the interactive password-change flow.
Preserve password-change enforcement for human accounts and restrictions
for inactive or prohibited accounts.

Fixes: https://github.com/go-gitea/gitea/issues/39542
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>

services/context/user.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	user_model "gitea.dev/models/user"
+	"gitea.dev/modules/session"
 )
 
 // UserAssignmentWeb returns a middleware to handle context-user assignment for web routes
@@ -58,3 +59,7 @@ func userAssignment(ctx *Base, doer *user_model.User, errCb func(int, string)) (
 	}
 	return contextUser
 }
+
+func IsDoerSessionImpersonated(sess session.Store) bool {
+	return sess.Get(session.KeyImpersonatorData) != nil
+}