fix for #802

Find an additional required header for pulse protocol. This header must contain a JSON.

According to #802 (comment 2691316833), such values exists, but, I do not find any docs on them:

• Supports512Routes
• Supports2048Routes
• supportSHA2Signature
• SupportsLastLoginDetails
• SupportsMixedModeESP
• SupportsSingleStackIPv6

Closes #802 (closed)