Use GetLocalMRPConfig for LivenessCheckTimerTimeout (#31466)

* Use GetLocalMRPConfig for LivenessCheckTimerTimeout

* address comment

* Restyled by clang-format

---------

Co-authored-by: Restyled.io <commits@restyled.io>
diff --git a/src/app/ReadClient.cpp b/src/app/ReadClient.cpp
index 77a8e4c..4a123fe 100644
--- a/src/app/ReadClient.cpp
+++ b/src/app/ReadClient.cpp
@@ -945,7 +945,9 @@
     // TODO: We need to find a good home for this logic that will correctly compute this based on transport. For now, this will
     // suffice since we don't use TCP as a transport currently and subscriptions over BLE aren't really a thing.
     //
-    const auto & ourMrpConfig = GetDefaultMRPConfig();
+    const auto & localMRPConfig   = GetLocalMRPConfig();
+    const auto & defaultMRPConfig = GetDefaultMRPConfig();
+    const auto & ourMrpConfig     = localMRPConfig.ValueOr(defaultMRPConfig);
     auto publisherTransmissionTimeout =
         GetRetransmissionTimeout(ourMrpConfig.mActiveRetransTimeout, ourMrpConfig.mIdleRetransTimeout,
                                  System::SystemClock().GetMonotonicTimestamp(), ourMrpConfig.mActiveThresholdTime);