Fix org permission API visibility checks for hidden members and private orgs (#36798)

- fix wrong parameter of HasOrgOrUserVisible in
routers/api/v1/org/org.go
- add integration tests covering the bug fix
- merge permissions API tests

---
Generated by a coding agent with Codex 5.2

routers/api/v1/org/org.go

@@ -135,7 +135,7 @@ func GetUserOrgsPermissions(ctx *context.APIContext) {
 
 	op := api.OrganizationPermissions{}
 
-	if !organization.HasOrgOrUserVisible(ctx, o, ctx.ContextUser) {
+	if !organization.HasOrgOrUserVisible(ctx, o, ctx.Doer) {
 		ctx.APIErrorNotFound("HasOrgOrUserVisible", nil)
 		return
 	}