1b5bec78e9 init: avoid unsetting service bits from `nLocalServices` (Sebastian Falbesoner)
Pull request description:
This PR is a late follow-up to the [review club session about the PR "Default to NODE_WITNESS in nLocalServices" ](https://bitcoincore.reviews/21090#l-90) (#21090):
```
17:32 <lightlike> hmm, if we are in pruned mode, we first set NODE_NETWORK and then unset it later in init.cpp. that seems a bit strange.
...
17:33 <jnewbery> lightlike: ah yes, you're right. That does seem a bit messy.
```
Rather than setting the service bit `NODE_NETWORK` first and then unset it (if in `fPruneMode`), start with the bare minimum flags that we always serve and only add `NODE_NETWORK` if we are running as a non-pruned node. This seems to be a more logical approach than currently on master.
ACKs for top commit:
naumenkogs:
ACK 1b5bec78e9
stickies-v:
ACK 1b5bec78e9
LarryRuane:
ACK 1b5bec78e9
Tree-SHA512: 2e82d66c4298ffacff41d9e0458b74b83bc156a1fa49e3f3471e942878e5dd2b253b5597ee5ec1d9c8726b432751d05e40f0c580f3976a9e00a7d1f417921ab0