Fix chat participant icons (#207652)

* Fix chat participant icons

* Update test

src/vs/workbench/contrib/chat/common/chatAgents.ts

@@ -218,7 +218,7 @@ export class ChatAgentService extends Disposable implements IChatAgentService {
 			{
 				extensionId: p.extensionId,
 				id: p.name,
-				metadata: { description: p.description },
+				metadata: this._agents.has(p.name) ? this._agents.get(p.name)!.data.metadata : { description: p.description },
 				isDefault: p.isDefault,
 				defaultImplicitVariables: p.defaultImplicitVariables,
 				locations: isNonEmptyArray(p.locations) ? p.locations.map(ChatAgentLocation.fromRaw) : [ChatAgentLocation.Panel],

src/vs/workbench/contrib/chat/test/common/__snapshots__/Chat_can_serialize.1.snap

@@ -22,7 +22,11 @@
             },
             agent: {
               id: "ChatProviderWithUsedContext",
-              metadata: { description: undefined }
+              metadata: {
+                description: undefined,
+                requester: { name: "test" },
+                fullName: "test"
+              }
             }
           },
           {
@@ -54,7 +58,11 @@
           value: "nullExtensionDescription",
           _lower: "nullextensiondescription"
         },
-        metadata: { description: undefined },
+        metadata: {
+          description: undefined,
+          requester: { name: "test" },
+          fullName: "test"
+        },
         slashCommands: [  ],
         locations: [ 1 ],
         isDefault: undefined