Add fix for GetChannelPaylodSupport

Currently `getChannelName` throws when the channel number
is invalid.
Because of which the error reported is Unspecified.

Example:
root@gb200nvl-obmc:~# ipmitool raw 0x06 0x4E 0x4
[1] Unable to send RAW command (channel=0x0 netfn=0x6 lun=0x0 cmd=0x4e rsp=0xff): Unspecified error

Added a patch to handle this gracefully

Tested:
Tested on gb200nvl-obmc platform
root@gb200nvl-obmc:~# ipmitool raw 0x06 0x4E 0x4
[2] Unable to send RAW command (channel=0x0 netfn=0x6 lun=0x0 cmd=0x4e rsp=0xcc): Invalid data field in request

Change-Id: Ibc9981d5e7143311f28bb9191fed4d68cd81356b
Signed-off-by: Prithvi Pai <ppai@nvidia.com>
diff --git a/user_channel/channel_layer.cpp b/user_channel/channel_layer.cpp
index 26bc3fa..e59459f 100644
--- a/user_channel/channel_layer.cpp
+++ b/user_channel/channel_layer.cpp
@@ -30,7 +30,14 @@
     // associated with ethernet interface as the channel number to
     // eth association is not done. Need to revisit later
     struct stat fileStat = {};
-    std::string devName("/sys/class/net/" + getChannelName(chNum));
+    auto channelName = getChannelName(chNum);
+    if (channelName.empty())
+    {
+        lg2::error("Channel name does not exist for channel {CHANNEL}",
+                   "CHANNEL", chNum);
+        return false;
+    }
+    std::string devName("/sys/class/net/" + channelName);
 
     if (stat(devName.data(), &fileStat) != 0)
     {
diff --git a/user_channel/channel_mgmt.cpp b/user_channel/channel_mgmt.cpp
index 77297c4..e3658eb 100644
--- a/user_channel/channel_mgmt.cpp
+++ b/user_channel/channel_mgmt.cpp
@@ -152,7 +152,7 @@
     {
         lg2::error("Get channel name - Invalid channel number: {CHANNEL_ID}",
                    "CHANNEL_ID", chNum);
-        throw std::invalid_argument("Invalid channel number");
+        return "";
     }
 
     return channelData[chNum].chName;