Investigate potentially flaky Highway Zug rewards tests

[SaiProServ]

While working on unrelated features, it was observed that the recently added tests for Zug rewards sometimes fail. The failures seem to be unrelated to CL_TEST_SEED and so far were not observed on the CI. There could be some timing issues involved.

Here are some example failures:

thread 'reactor::main_reactor::tests::run_reward_network_highway_no_finality' panicked at 'missing switch block', node/src/reactor/main_reactor/tests.rs:747:29

============================================================================
Thread: reactor::main_reactor::tests::run_reward_network_highway_no_finality
To reproduce failure, try running with env var:
CL_TEST_SEED=0608a0974e8da01203cc8611c9e515cb
============================================================================

test reactor::main_reactor::tests::run_reward_network_highway_no_finality ... FAILED`

==========================================================================================
Thread: reactor::main_reactor::tests::run_reward_network_highway_all_finality_zero_finders
To reproduce failure, try running with env var:
CL_TEST_SEED=11ad44d1c4233aee7b34b1c755bc742e
==========================================================================================

test reactor::main_reactor::tests::run_reward_network_highway_all_finality_zero_finders ... FAILED`

The panic message mentions missing switch block, just panicked at 'called Option::unwrap() on a None value' or 'should have stored switch block header for era 2 within 600 seconds' (possibly also other)

[devendran-m]

Moved it back to backlog for prioritisation.

[devendran-m]

Closing as won't do