fix: avoid duplicate AfterAssemblyDataReceived callback for Assembly attribute 3

[MrAlaskan]

Summary

This PR removes a duplicate AfterAssemblyDataReceived() callback for explicit SetAttributeSingle writes to Assembly Attribute 3.

Problem

The Assembly class installs a class-level PostSetCallback, and Assembly Attribute 3 is also created with the kPostSetFunc flag. As a result, SetAttributeSingle() calls the attribute decoder first and then invokes the class-level post-set callback for the same write.

However, DecodeCipAssemblyAttribute3() already calls AfterAssemblyDataReceived(instance) after copying the new Assembly data. The Assembly class post-set callback AssemblyPostSetCallback() also calls AfterAssemblyDataReceived(instance). This means that one explicit SetAttributeSingle(Attribute 3) request deterministically produces two application-level data-received notifications for the same write.

This duplicates side effects for applications that use AfterAssemblyDataReceived() to trigger state changes, hardware updates, counters, logging, or other non-idempotent processing. It also makes the explicit write path inconsistent with the intended one-request, one-update event model.

Changes

• Remove kPostSetFunc from Assembly Attribute 3 when the attribute is created in CreateAssemblyObject().
• Keep the existing AfterAssemblyDataReceived() call inside DecodeCipAssemblyAttribute3() so that successful explicit writes still notify the application once.