[Workflow Interface]: Fix for FederatedRuntime with TLS (Issue #1265)

[ishant162]

Background
Issue: #1265

Change Description & Modifications

• Updated the agg_addr field to use the Director's hostname and Synchronized the TLS configuration with the values provided by FederatedRuntime in the
  network section of plan.yaml for alignment with the system configuration.
• Ensured all changes made to plan.yaml are correctly propagated to the prepared workspace.
• Updated network.yaml by removing unused keys from its settings.

Verfication

• Verified that the agg_addr is correctly updated with the Director's hostname in plan.yaml, preventing recurrence of the issue.
• Verified that the experiment runs successfully with mTLS certificates generated using both localhost and the machine's FQDN (e.g soc-PF2F2E02.clients.intel.com)
  as the Common Name for the Director's certificates.

Files modified

• openfl/experimental/workflow/federated/plan/plan.py
• openfl/experimental/workflow/runtime/federated_runtime.py
• openfl/experimental/workflow/workspace_export/export.py
• openfl-workspace/experimental/workflow/AggregatorBasedWorkflow/workspace/plan/defaults/network.yaml

NOTE
The Director Admin must ensure mTLS certificates have the correct Common Name (CN), matching the hostname in the Director's configuration. Envoy Admin and Experiment Manager must use this hostname to facilitate proper communication and prevent connectivity issues.

This PR fixes #1265

[teoparvanov]

LGTM, @ishant162! Thanks for the fixes, and for the detailed background which helped me a lot as a reviewer of the proposed code changes.