fix: apns production option

[michaldziuba03]

What change does this PR introduce?

Add default value for apns production option. Undefined value leads to unexpected behaviour.

Why was this change needed?

Closes #3416 - everything is well described in this issue

https://github.com/node-apn/node-apn#connecting

By default, the provider will connect to the sandbox unless the environment variable NODE_ENV=production is set

Basically when user creates APNs integration, by default it creates credentials where secure is optional field so it's undefined when value not specified (secure field is used for production option for node-apn). So when secure is undefined, then node-apn package uses NODE_ENV to determine if production is true or false. It may lead to scenario where user has production set to undefined (in GUI it's switch which indicates that production should be disabled) but Novu servers are probably running with NODE_ENV=production and then we have bug or at least possible unexpected behaviour.

Important note - this PR is very closely related to PR#3430. 3430 solves other problem where secure used for production field is persisted as string, so if someone provides "false" then it's interpreted by node-apn as true value what makes whole provider just broken actually.

Other information (Screenshots)

[p-fernandez]

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