platform-mc: Suppress expected discovery errors

Downgraded various expected discovery conditions from errors to
warnings to match the legacy pldmd-google behavior and reduce
log spam.
- In terminus.cpp, downgraded unsupported FRU Record ID types
  to warning.
- In platform_manager.cpp, gracefully handle unsupported
  SetEventReceiver command by returning PLDM_SUCCESS and
  logging a warning.
- In mctp_endpoint_discovery.cpp, explicitly handle missing
  UUID interfaces by logging a warning instead of an error.

Tested:
Verified that the previously observed errors for unsupported
FRU types, missing event receiver support, and missing
MCTP UUID interfaces are no longer generated as errors in the
system log on platform31, matching the baseline log output.

Change-Id: I177c3bc10a860fc26fecf360ff0b15cb97aff7ba
Google-Bug-Id: 458166668
Signed-off-by: Luka Strizic <lstrz@google.com>

platform-mc/platform_manager.cpp

diff --git a/platform-mc/platform_manager.cpp b/platform-mc/platform_manager.cpp
index 85ff9b7..81a88c5 100644
--- a/platform-mc/platform_manager.cpp
+++ b/platform-mc/platform_manager.cpp
@@ -163,8 +163,8 @@
 
     if (!terminus->doesSupportCommand(PLDM_PLATFORM, PLDM_SET_EVENT_RECEIVER))
     {
-        lg2::error("Terminus {TID} does not support Event", "TID", tid);
-        co_return PLDM_ERROR;
+        lg2::warning("Terminus {TID} does not support Event", "TID", tid);
+        co_return PLDM_SUCCESS;
     }
 
     /**

platform-mc/terminus.cpp

diff --git a/platform-mc/terminus.cpp b/platform-mc/terminus.cpp
index fc492af..1fda123 100644
--- a/platform-mc/terminus.cpp
+++ b/platform-mc/terminus.cpp
@@ -767,7 +767,7 @@
 
         if (record->record_type != PLDM_FRU_RECORD_TYPE_GENERAL)
         {
-            lg2::warning(
+            lg2::info(
                 "Does not support Fru Record ID Type {TYPE} of terminus {TID}",
                 "TYPE", record->record_type, "TID", tid);
 

requester/mctp_endpoint_discovery.cpp

diff --git a/requester/mctp_endpoint_discovery.cpp b/requester/mctp_endpoint_discovery.cpp
index 1ab5e7e..a0b63bc 100644
--- a/requester/mctp_endpoint_discovery.cpp
+++ b/requester/mctp_endpoint_discovery.cpp
@@ -167,8 +167,12 @@
     }
     catch (const sdbusplus::exception_t& e)
     {
-        error(
-            "Error reading Endpoint UUID property at path '{PATH}' and service '{SERVICE}', error - {ERROR}",
+        // UUID is an optional interface for MCTP endpoints in OpenBMC.
+        // It is perfectly valid for an endpoint not to implement the
+        // Common.UUID interface. We log a warning instead of an error and
+        // safely proceed with an empty UUID.
+        warning(
+            "Could not read Endpoint UUID property at path '{PATH}' and service '{SERVICE}', error - {ERROR}",
             "SERVICE", service, "PATH", path, "ERROR", e);
         return static_cast<UUID>(emptyUUID);
     }