Register accumulators for nested ScanningRecipes in OR preconditions

[Jenson3210]

Summary

• Fix NPE when using OR preconditions with nested ScanningRecipes
• Add recursive registration and scanning of nested ScanningRecipes in DeclarativeRecipe
• Add comprehensive tests for nested OR preconditions scenarios

Problem

When using the OR precondition pattern with ScanningRecipes like ModuleHasDependency or RepositoryContainsFile, the recipes fail with a NullPointerException:

java.lang.NullPointerException: Cannot invoke "java.util.concurrent.atomic.AtomicBoolean.get()" because "acc" is null
    at org.openrewrite.search.RepositoryContainsFile.getVisitor(RepositoryContainsFile.java:73)
    at org.openrewrite.config.DeclarativeRecipe.orVisitors(DeclarativeRecipe.java:483)

The root cause is that getInitialValue() only registers direct preconditions, but orVisitors() recursively looks up nested ScanningRecipes in precondition recipes' recipeLists that were never registered.

Solution

Added two helper methods that recursively traverse precondition recipes' recipeLists:

1. registerNestedScanningRecipes() - Called from getInitialValue() to register all nested ScanningRecipes in the accumulator map
2. scanNestedScanningRecipes() - Called from getScanner() to invoke the scanner on all nested ScanningRecipes

Test plan

• Existing tests pass

• New tests added covering:

  • Basic nested ScanningRecipe in OR precondition
  • Precondition not met scenario
  • Same scanning recipe type with different parameters
  • Deeply nested OR preconditions (3 levels deep)
  • Multiple branches with same scanning recipe

• Fixes DeclarativeRecipe doesn't register accumulators for nested ScanningRecipes in OR preconditions #6698