Refactor verify: split session validation and validateAndDispatchMsg (#939)

[wilson-zh]

Fix #939: Remove unreachable session verification logic

Refactor Session/verify by moving fromCallBack call outside verify, therefore preserves:

1. original validation order and behavior
2. accurate method description

[chrjohn]

Hi @wilson-zh , thanks for the PR. There is an error in the tests:

2025-12-02T07:24:37.2419690Z quickfix.RuntimeError: java.lang.StackOverflowError
2025-12-02T07:24:37.2420510Z 	at quickfix.Session.next(Session.java:1237)
2025-12-02T07:24:37.2421129Z 	at quickfix.Session.next(Session.java:1284)
2025-12-02T07:24:37.2422384Z 	at quickfix.mina.SingleThreadedEventHandlingStrategy$SessionMessageEvent.processMessage(SingleThreadedEventHandlingStrategy.java:163)
2025-12-02T07:24:37.2424244Z 	at quickfix.mina.SingleThreadedEventHandlingStrategy.block(SingleThreadedEventHandlingStrategy.java:113)
2025-12-02T07:24:37.2425842Z 	at quickfix.mina.SingleThreadedEventHandlingStrategy.lambda$blockInThread$1(SingleThreadedEventHandlingStrategy.java:145)
2025-12-02T07:24:37.2427617Z 	at quickfix.mina.SingleThreadedEventHandlingStrategy$ThreadAdapter$RunnableWrapper.run(SingleThreadedEventHandlingStrategy.java:270)
2025-12-02T07:24:37.2428922Z 	at java.lang.Thread.run(Thread.java:750)
2025-12-02T07:24:37.2429531Z Caused by: java.lang.StackOverflowError
2025-12-02T07:24:37.2430238Z 	at quickfix.Session.validateAndDispatchMsg(Session.java:1804)

The builds were in an endless loop, I just cancelled them.

Could you please take a look at it? Thank you