[wallet_bridge_api] Problem with checking required API activity

An issue has been found with wallet_bridge_api related to interfacing with other APIs. Checking in wallet_bridge_api for active APIs required for it to work properly is not working properly. The wallet_bridge_api works until you call a method that requires an inactive API to work. For example, everything was ok until you called find_rc_accounts without rc_api_plugin. Then the program crashes. No exception is reported.

Suggested solutions to this situation are : (a) returning an empty response b) returning appropriate information e.g. "Plugin wasn't activated".