Fix repository TryFindByIdAsync (#416)

### Motivation and Context
Repository TryFindByIdAsync would not try to find anything if no
callback was passed to it, hence always returning true, even when no
entries were found!

### Description
Always doing a true search because executing any callback with the
result.

### Contribution Checklist
- [ ] The code builds clean without any errors or warnings
- [ ] The PR follows the [Contribution
Guidelines](https://github.com/microsoft/chat-copilot/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/chat-copilot/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [ ] All unit tests pass, and I have added new tests where possible

webapi/Program.cs

@@ -92,7 +92,7 @@ public static async Task Main(string[] args)
             .RequireAuthorization();
         app.MapHealthChecks("/healthz");
 
-        // Add CopilotChat hub for real time communication
+        // Add Chat Copilot hub for real time communication
         app.MapHub<MessageRelayHub>("/messageRelayHub");
 
         // Enable Swagger for development environments.

webapi/Storage/Repository.cs

@@ -29,7 +29,7 @@ public Task CreateAsync(T entity)
     {
         if (string.IsNullOrWhiteSpace(entity.Id))
         {
-            throw new ArgumentOutOfRangeException(nameof(entity.Id), "Entity Id cannot be null or empty.");
+            throw new ArgumentOutOfRangeException(nameof(entity.Id), "Entity ID cannot be null or empty.");
         }
 
         return this.StorageContext.CreateAsync(entity);
@@ -52,7 +52,10 @@ public async Task<bool> TryFindByIdAsync(string id, string? partition = null, Ac
     {
         try
         {
-            callback?.Invoke(await this.FindByIdAsync(id, partition ?? id));
+            T? found = await this.FindByIdAsync(id, partition ?? id);
+
+            callback?.Invoke(found);
+
             return true;
         }
         catch (Exception ex) when (ex is ArgumentOutOfRangeException || ex is KeyNotFoundException)