Prepare for 1.5.55.1 release

[Aaronontheweb]

Summary

Release preparation for version 1.5.55.1

Changes

• Updated RELEASE_NOTES.md with version 1.5.55.1 entry
• Updated Directory.Build.props with new version and release notes
• Includes enhancement from PR feat(persistence): expose options in journal and snapshot builders #691: Expose options in journal and snapshot builders

Release Notes

Enhancements

• Expose options in journal and snapshot builders - resolved issue #690 by adding Options property to AkkaPersistenceJournalBuilder and AkkaPersistenceSnapshotBuilder. Extension methods can now access configuration details without requiring options as explicit parameters, eliminating redundant option passing for connectivity health checks and other plugin-specific features