apollo_integration_tests: fix port allocation to generate unique ports per node

[nadin-Starkware]

Note

Low Risk
Small, localized change to test-only port allocation; main risk is unintended shifts in port assignment that could reveal hidden assumptions in existing tests.

Overview
Fixes integration-test node setup so each node gets its own fresh AvailablePorts allocation when generating configs.

get_sequencer_setup_configs now advances the AvailablePortsGenerator inside the per-node creation loop rather than once for all nodes, preventing multiple nodes from accidentally sharing the same port pool and colliding at runtime.

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[reviewable-StarkWare]

This change is 

[nadin-Starkware]

• apollo_storage: always spawn storage reader server, return 503 when disabled #12836 : 2 dependent PRs (#12876 , #12940 )
• apollo_storage: abort storage reader server handles on drop #12843
• apollo_integration_tests: fix port allocation to generate unique ports per node #12855 👈 (View in Graphite)
• main-v0.14.2

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[Itay-Tsabary-Starkware]

@Itay-Tsabary-Starkware reviewed 1 file and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on nadin-Starkware).