storcon: add peer jwt token (#8764)

## Problem

Storage controllers did not have the right token to speak to their peers
for leadership transitions.

## Summary of changes

Accept a peer jwt token for the storage controller.

Epic: https://github.com/neondatabase/cloud/issues/14701

test_runner/regress/test_storage_controller.py

@@ -2144,6 +2144,8 @@ def test_storage_controller_leadership_transfer(
     port_distributor: PortDistributor,
     step_down_times_out: bool,
 ):
+    neon_env_builder.auth_enabled = True
+
     neon_env_builder.num_pageservers = 3
 
     neon_env_builder.storage_controller_config = {