fuzz: connman: strengthen assertions and extend coverage #35220

This PR improves the connman fuzz target by replacing some "(void)" calls with actual invariant checks, adding coverage for previously uncovered methods, and exercising more initialization states.

• Set m_local_services, m_use_addrman_outgoing, and m_max_automatic_connections via fuzzed values before Init() to explore more startup configurations.

• Add network activity and outbound-bytes invariants.

• Add AddNode/RemoveAddedNode invariants: e.g. a successful AddNode increases GetAddedNodeInfo() by one; adding the same node again must fail; a subsequent RemoveAddedNode must succeed and restore the original count.

• Add coverage for AddLocalServices/RemoveLocalServices.

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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35220.

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Reviews

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #34934 (fuzz: exercise ForNode/ForEachNode callbacks in connman fuzz harness by frankomosh)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

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