refactor(amazonq): Removing unwanted / agents code (aws#7735)

## Problem
- There is lot of duplicate and unwanted redundant code in
[aws-toolkit-vscode](https://github.com/aws/aws-toolkit-vscode)
repository.

## Solution

- This is the first PR to remove unwanted code.
---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: laileni-aws

packages/amazonq/src/app/chat/node/activateAgents.ts

@@ -11,9 +11,6 @@ export function activateAgents() {
     const appInitContext = DefaultAmazonQAppInitContext.instance
 
     amazonqNode.cwChatAppInit(appInitContext)
-    amazonqNode.featureDevChatAppInit(appInitContext)
     amazonqNode.gumbyChatAppInit(appInitContext)
-    amazonqNode.testChatAppInit(appInitContext)
-    amazonqNode.docChatAppInit(appInitContext)
     scanChatAppInit(appInitContext)
 }