Inliner removes some functions used by the debugger

[jfecher]

Aim

Discovered in #6894, the SSA inlining pass can remove functions used in the debugger.

Expected Behavior

The inlining pass shouldn't remove any functions that are still in use

Bug

In the higher_order_functions test, inlining will remove functions still referenced by the debugger, although the remaining SSA passes seem unbothered by this.

To Reproduce

1. Comment out the normalize_ids() pass in compiler/noirc_evaluator/src/ssa.rs line 493
2. $ cd test_programs/execution_success/higher_order_functions
3. $ cargo run debug --force-brillig --show-ssa > ssa
4. Inspect the resulting SSA to find f13 is still used after the first inlining pass but there is no longer a corresponding fn lambda f13 in the program.

Workaround

None

Workaround Description

No response

Additional Context

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Project Impact

None

Blocker Context

No response

Nargo Version

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NoirJS Version

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Proving Backend Tooling & Version

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Would you like to submit a PR for this Issue?

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Support Needs

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