server/v2: state pruning during export genesis

[akhilkumarpilli]

Below issue encountered when testing genesis export in v2:

• When exporting genesis without specifying a height, the export takes place at the current node height. For example, if the node is stopped at height 8 and genesis is exported without specifying a height, it exports at height 8 without any issue.
• Exporting genesis at an earlier height (e.g., height 2) succeeds, but the state after height 2 is pruned, and the node's latest height becomes 2.
• If we try to export at a higher height (like 4) afterward, I encounter this error: error exporting state: failed to load SC version 4: wanted to load target 4 but only found up to 2.