Handling the any state correctly when using a nested state machine

[vasdal]

Problem:

• Any state does not work if there is a nested state machine within a state machine with any state, as demonstrated in the failing test any_state_nested.

Solution:

• Modified the get_state_mapping specialization for nested state machines to consider both direct state transitions and any state transitions.
• The implementation now tries direct transitions first, and if those don't handle the event, it falls back to any state transitions.
• This ensures consistent behavior between regular states and nested state machines when using the any state.

Issue: #622

Reviewers:
@kris-jusiak

[kris-jusiak]

Nice, thanks @vasdal 👍