[ EKS ] [ BUG ] [ 1.26 ] /etc/eks/bootstrap.sh subshell execution is not sourcing env by default causing failure in nodegroup creation

`/etc/eks/bootstrap.sh` gets executed when the node comes up which is executing a binary `/usr/bin/private-dns-name` as a subshell that does not inherit the env variable from `/etc/environment` because of which all the outbound communications are getting blocked resulting in the node not joining the nodegroup and failure in creation of the same

our environment has a proxy configured and the env has all the proxy details.

This issue comes only in 1.26 we didn't face any issues in 1.25

We added the below command in the binary `/usr/bin/private-dns-name` during runtime to solve the issue

```
set -a
source /etc/environment
```

Review /etc/eks/bootstrap.sh and /usr/bin/private-dns-name first, then examine how /etc/environment is handled during the EKS 1.26 node startup path. Done means proxy settings are available to the subshell and a proxied node successfully joins its nodegroup without the runtime workaround.

Written by the indexing model from the issue text.