Fix error reporting in Schedulers

[mikkolaj]

Summary

In JDK 25 ForkJoinPool implements ScheduledExecutorService. This change resulted in incorrect error reporting and failing tests in #6.

Problem

Monix has two internal implementations of ExecutorScheduler:

• FromSimpleExecutor - for regular ExecutorService
• FromScheduledExecutor - for ScheduledExecutorService

The FromScheduledExecutor implementation relies on error reporting being done by the underlying executor itself (via afterExecute hook), but this only works correctly with AdaptedThreadPoolExecutor (Monix's custom implementation). For other ScheduledExecutorService implementations, error reporting did not work properly.

Before JDK 25 this problem wasn't visible, because almost all Scheduler factory methods use AsyncScheduler, FromSimpleExecutor or FromScheduledExecutor together with AdaptedThreadPoolExecutor.

Additionally, withUncaughtExceptionReporter didn't work correctly for all scheduler methods in wrapped schedulers (AsyncScheduler, etc.) - the updated reporter wasn't being used for scheduleOnce, scheduleAtFixedRate, and scheduleWithFixedDelay.

Changes

1. Restricted FromScheduledExecutor (now FromAdaptedThreadPoolExecutor) usage - This implementation is now only used for schedulers backed by AdaptedScheduledThreadPoolExecutor. All other ExecutorService implementations (including ScheduledExecutorService and ForkJoinPool) use FromSimpleExecutor.

2. Fixed error reporting in wrapped schedulers (ReferenceScheduler) - The scheduleOnce, scheduleAtFixedRate, and scheduleWithFixedDelay methods now wrap runnables with InterceptRunnable to pass exceptions to correct reporters.