Allow users to edit the sync interval for existing push mirrors. Currently, there is no way to modify the interval once the mirror is created. <details> <summary>Screenshots</summary> ## Before <img width="936" alt="Screenshot 2023-07-26 at 9 31 21 AM" src="https://github.com/go-gitea/gitea/assets/80308335/35b8a40c-4320-474c-a866-1dea0f1fa0de"> ## After <img width="945" alt="Screenshot 2023-07-26 at 9 44 40 AM" src="https://github.com/go-gitea/gitea/assets/80308335/ee12e12f-0f68-4feb-90eb-33366f5997d3"> ### On hover <img width="247" alt="image" src="https://github.com/go-gitea/gitea/assets/80308335/2f32de45-bd50-4150-9623-3be2ef3ea7f8"> <img width="237" alt="image" src="https://github.com/go-gitea/gitea/assets/80308335/49f4ab4d-ccff-4489-80ce-a9788a73c3bb"> <img width="245" alt="image" src="https://github.com/go-gitea/gitea/assets/80308335/165fc888-9d48-438a-b730-d4beb12122af"> ### Edit modal <img width="905" alt="image" src="https://github.com/go-gitea/gitea/assets/80308335/2a7ca24b-4f36-4e0e-9799-39f2ecc46413"> ### Only valid times are allowed <img width="728" alt="Screenshot 2023-07-26 at 9 50 01 AM" src="https://github.com/go-gitea/gitea/assets/80308335/ced6d330-c235-4e29-8f17-28daddcf1444"> <img width="853" alt="image" src="https://github.com/go-gitea/gitea/assets/80308335/8636f62a-70d1-4684-a3e8-b205adc03580"> </details> Fixes #21295 --------- Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
