Add a secondary reminder for special characters when saving changes to the secret authentication

[lukaixiao]

Description: A couple of days ago, a student in the Cloud SRS group said that they could push the RTMP stream but couldn't push the SRT stream. They asked for help to find out the reason. After struggling for a day, it was finally discovered that they had changed the secret authentication string, and the secret string contained special characters. After modifying it, the stream push was normal.

Suggestion: When modifying and saving the secret string, first verify it. If it contains special characters, display a pop-up reminder. If the user does not confirm the pop-up, do not save the changes. If the string does not contain special characters or the user confirms the pop-up, save the changes.

Faulty string: secret=efP&A@YJ^w5iHQ7A