MATTER-5951: Refrigerator app refactor

[Michael Duggan (miduggan24)]

Issue Link:
MATTER-5951

Description of Problem/Feature:
Extension PR to pick up project upgrades refactor for refrigerator app

Description of Fix/Solution:

• Bump submodule to latest matter_sdk (needs [SL-UP] MATTER-5951: Refrigerator app refactor matter_sdk#1004)
• Update necessary slcp/slcw files
• Update README files

Testing Done:
CI (full run with smoke)
Local testing of overrides

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Note

Medium Risk
Restructures which sources and generated files compile into the refrigerator firmware; regressions would show up as build or runtime behavior changes until the paired matter_sdk bump lands.

Overview
Aligns Thread and Wi‑Fi refrigerator SLC projects with the post–project-upgrade app structure: app logic is no longer wired in via direct AppTask.cpp, RefrigeratorManager.cpp, DataModelCallbacks.cpp, and related headers in the .slcp files. Builds now pull CustomerAppTask from the shared Silicon Labs customer platform layer and register RefrigeratorConfig.h as a config file.

The matter_refrigerator component now templates AppTask.h, AppTaskImpl.h, and AppTask.cpp into autogen/, so defaults and overridable *Impl() APIs are generated at build/upgrade time rather than living only in the example tree.

Documentation: both refrigerator READMEs gain an Extending Base App Implementation section (TOC link included) that explains CRTP overrides in CustomerAppTask, where attribute callbacks moved after removing DataModelCallbacks.cpp, and sample AppInitImpl / ButtonEventHandlerImpl code plus pointers to autogen/AppTaskImpl.h and autogen/AppTask.cpp.

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