[addon-operator] Fix/readiness bug

[timmilesdw]

Overview

Fix "multiple readiness hooks found" false positive error during module hook registration retry.

What this PR does / why we need it

When RegisterHooks() fails after searchModuleBatchHooks() has already found a readiness hook (e.g., error in AssembleEnvironmentForModule()), the hasReadiness flag remains true while hooks.registered stays false. On retry, searchModuleBatchHooks() finds the same readiness hook again but sees hasReadiness already set to true, incorrectly reporting "multiple readiness hooks found".

Root cause: searchModuleBatchHooks() was modifying bm.hasReadiness as a side effect during the search, before registration was complete.

Fix: Refactored searchModuleBatchHooks() to be a pure function that returns hasReadiness as a separate value instead of modifying the struct field directly. The bm.hasReadiness field is now set only in RegisterHooks() after successful registration.