Pushover acknowledge receipt doesn't work

[yodax]

Describe the bug
When a pushover critical notification is acknowledged the alarm isn't suspended. An error appears in the log.

To Reproduce
Steps to reproduce the behavior:

1. Acknowledge a critical notification
2. Check logs

Expected behavior
The alarm should be suspended.

Screenshots

TypeError: Cannot read property 'receipt' of undefined
    at Function.pushoverAck (/usr/home/nightscout/cgm-remote-monitor/lib/server/pushnotify.js:59:19)
    at /usr/home/nightscout/cgm-remote-monitor/lib/api/notifications-api.js:11:24
    at Layer.handle [as handle_request] (/usr/home/nightscout/cgm-remote-monitor/node_modules/express/lib/router/layer.js:95:5)
    at next (/usr/home/nightscout/cgm-remote-monitor/node_modules/express/lib/router/route.js:137:13)
    at Route.dispatch (/usr/home/nightscout/cgm-remote-monitor/node_modules/express/lib/router/route.js:112:3)
    at Layer.handle [as handle_request] (/usr/home/nightscout/cgm-remote-monitor/node_modules/express/lib/router/layer.js:95:5)
    at /usr/home/nightscout/cgm-remote-monitor/node_modules/express/lib/router/index.js:281:22
    at Function.process_params (/usr/home/nightscout/cgm-remote-monitor/node_modules/express/lib/router/index.js:335:12)
    at next (/usr/home/nightscout/cgm-remote-monitor/node_modules/express/lib/router/index.js:275:10)
    at Function.handle (/usr/home/nightscout/cgm-remote-monitor/node_modules/express/lib/router/index.js:174:3)

Your setup information

• What version of Nightscout 14.2.4
• Pushover on iOS.
• Nightscout is behind a HAProxy TLS offloading proxy. Nightscout is running on FreeBSD (13.0-RELEASE) with Node 14
• pm2 env: node_version: 14.18.1 version: 14.2.4
• This worked with the previous release of nightscout on Node 12. (Node 12 was removed from the FreeBSD package due to security issues)

Still the same with Nightscout 14.2.6 on Debian 10.13, node 16.8.1

[yodax]

Fixed by: #7876