deps(dependencies): Address high-severity vulnerabilities by updating dependencies (aws#5511)

## Problem

The aws-toolkit-vscode repository has several high-severity
vulnerabilities in its dependencies, as identified by the npm audit
command. These vulnerabilities, if left unaddressed, could pose a
security risk to users of the AWS Toolkit for VS Code extension.

The vulnerabilities include:

- elliptic package versions 2.0.0 to 6.5.6 have multiple vulnerabilities
related to EDDSA, ECDSA, and BER-encoded signatures.
- es5-ext package versions 0.10.1 to 0.10.62 are vulnerable to Regular
Expression Denial of Service (ReDOS) in the function#copy and
function#toStringTokens functions.
- fast-xml-parser package versions prior to 4.4.1 are vulnerable to
ReDOS at currency parsing.

## Solution

To address these high-severity vulnerabilities, this pull request
updates the dependencies in the aws-toolkit-vscode repository:

- The elliptic package is upgraded from version 6.5.3 to 6.5.4 to
address the EDDSA, ECDSA, and BER-encoded signatures vulnerabilities.
- The es5-ext package is upgraded from version 0.10.53 to 0.10.62 to
address the ReDOS vulnerability in the function#copy and
function#toStringTokens functions.
- The fast-xml-parser package is upgraded from version 3.19.0 to 4.4.1
to address the ReDOS vulnerability at currency parsing.

## Implementation Details:

By updating the following top level dependencies, the underlying
transitive dependencies with the vulnerabilities were updated to a safe
version:

- `@aws-sdk/client-cognito-identity`
- `@aws-sdk/client-lambda`

---

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License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Co-authored-by: Keen Wilson <[email protected]>

Author: keenwilson

CHANGELOG.md

@@ -0,0 +1,4 @@
+## [Unreleased]
+
+### Fixed
+- Addressed high-severity vulnerabilities in dependencies by updating `elliptic` to 6.5.4, `es5-ext` to 0.10.62, and `fast-xml-parser` to 4.4.1. [#5511](https://github.com/aws/aws-toolkit-vscode/pull/5511)