Invalid QR Codes generated

[FredFromUmt]

If you use
var uriString = new OtpUri(OtpType.Totp,secretBytes,userName,issuer);
the secretBytes will undergo the transformation
Base32Encoding.ToString(secret)
in the constructor.
It is entirely possible, that the resulting string ends with an equal sign '='.
In that case, should you put the resulting string in a QR Code generator and try to scan it:

• Google Authenticator will inform you that it is not a valid uri.
• Microsoft Authenticator will freeze the camera roll and refuse to work until restarted.
• Tested on iOS 16.3.1

The string needs to be sanitized, if you remove the trailing '=' character(s), both apps will recognize the Code as valid.

Suggested change in the public override string ToString():
Dictionary<string, string> dictionary = new Dictionary<string, string>() { { "secret", this.Secret } };
to
Dictionary<string, string> dictionary = new Dictionary<string, string>() { { "secret", this.Secret.TrimEnd('=') } };
might be enough to fix it.