S3 Event Source for Lambda Functions in AWS Toolkit

**Describe the bug**

S3 Event Sources do not show up in the "Event Sources" tab of the Lambda Function window in the toolkit.

**To Reproduce**

1. Open any Lambda function using the AWS toolkit for VS.
2. Choose the "Event Sources" tab
3. Choose "+ Add"
4. For "Source Type", select "Amazon S3". Select a bucket you want to use.
5. Choose "OK"

Once you have done this, the event sources area is still blank. The event source is successfully applied (you can see it in the console). Plus if you try to re-add the same bucket, you get an error that you are trying to add a duplicate.

So the issue appears to be that it just does not show up in the list, other event sources, like SQS, do. The event source is created correctly in AWS.

**Expected behavior**

The expected behavior is that when you add an S3 event source, it will show up in the event sources area.

**Screenshots**

1 - Choose S3 Event Source

2 - What it looks like in Toolkit after S3 Event Source is Chosen

3 - S3 Event Source is Present in Console

4 - Try to Readd S3 Event Source - Error

**Computer (please complete the following information):**

- Windows Version: Windows 11 21H2 (22000.2295)
- Visual Studio Version: VS 2022 Pro - 17.7.0
- AWS Toolkit for Visual Studio Version: 1.42.0.0

**Additional context**

Reproduce the issue through the Lambda Function window's Event Sources tab: add an Amazon S3 bucket and confirm that the event source is created but not listed. No source file or test is named, so first trace the Event Sources UI and S3-specific listing path; done means an added S3 source appears in the list without breaking duplicate detection.

Written by the indexing model from the issue text.