fix(examples): Set record to the Waku Node Builder as it is required.

[EmilIvanichkovv]

Description

I followed the instructions in the examples readme. After running make example2, everything appeared to be in order. However, when executing ./build/subscriber, I encountered the following message:

NTC 2024-01-02 16:50:37.824+02:00 starting subscriber                        tid=132009 file=subscriber.nim:35 wakuPort=50000 discv5Port=8000
/some/nice/path/nwaku/examples/subscriber.nim(102) subscriber
/some/nice/path/nwaku/vendor/nim-chronos/chronos/internal/asyncfutures.nim(660) cb
Error: unhandled exception: Asynchronous task [setupAndSubscribe() at subscriber.nim:34] finished with an exception "LPError"!
Message: node record is required
Stack trace: /some/nice/path/nwaku/examples/subscriber.nim(102) subscriber
/some/nice/path/nwaku/examples/subscriber.nim(34) setupAndSubscribe
/some/nice/path/nwaku/vendor/nim-chronos/chronos/internal/asyncfutures.nim(378) futureContinue
/some/nice/path/nwaku/examples/subscriber.nim(44) setupAndSubscribe
/some/nice/path/nwaku/vendor/nim-results/results.nim(840) tryValue
 [FutureDefect]

The error indicated that a "node record is required," so I addressed this by setting it to the Waku Node Builder object. After rebuilding and restarting both the subscriber and publisher, everything seems to be working correctly.

Changes

• Create enr record and set it to Waku Node Builder object in the examples

How to test

1. Follow the examples readme.

Issue

closes #2327

[jm-clius]

Thanks for fixing this!

[vpavlin]

LGTM