feat(amazonq): add MCP server support (#7451)

## Problem
- we are missing the `mcp: true` flag

## Solution
- add `mcp: true` flag to enable mcp server support

---

- 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: chungjac

packages/amazonq/.changes/next-release/Feature-57661731-6180-4157-a04b-d3a8b50aa1a8.json

@@ -0,0 +1,4 @@
+{
+	"type": "Feature",
+	"description": "Add MCP Server Support"
+}

packages/amazonq/src/lsp/client.ts

@@ -123,6 +123,7 @@ export async function startLanguageServer(
                 awsClientCapabilities: {
                     q: {
                         developerProfiles: true,
+                        mcp: true,
                     },
                     window: {
                         notifications: true,