fix: pass environment_offline through to the Gym actors

[anubhutivyas]

What does this PR do ?

• spinup_nemo_gym_actor rebuilds the sandboxed block from a fixed set of keys and omitted this one, so it silently took the model default: the compiled config said environment_offline: true while the sandbox got NMP_ENVIRONMENT_OFFLINE=0, and a wheels-v1 job reached for an index the deny-egress policy denies it.
• The colocated NemoGymConfig call omitted it the same way.

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