Unable to invoke lambda when "Authorization scopes" added to JWT Authorizer

*Serverless Java Container version*: `eg. 1.5.2`

*Implementations:* `Spring Boot 2`

*Framework version:* `eg SpringBoot 2.4.1`

*Frontend service:* `HTTP API`

*Deployment method:* `SAM`

## Scenario
*Describe what you are trying to accomplish*
I am trying to call invoke lambda via HTTP api with JWT authorizer. call to lambda are failing when i add "Authorization scopes" in the JWT authorizer(on HTTP api)

## Expected behavior
I would expect lambda should be able to be invoke with or without Authorization scopes in JWT authorizer

## Actual behavior
I am trying to call invoke lambda via HTTP api with JWT authorizer. call to lambda are failing when i add "Authorization scopes" in the JWT authorizer(on HTTP api) with error message

```com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.lang.String` out of START_ARRAY token
at [Source: (ByteArrayInputStream); line: 1, column: 3530] (through reference chain: com.amazonaws.serverless.proxy.model.AwsProxyRequest["requestContext"]->com.amazonaws.serverless.proxy.model.AwsProxyRequestContext["authorizer"]->com.amazonaws.serverless.proxy.model.ApiGatewayAuthorizerContext["scopes"])```

but without "Authorization scopes" in the JWT authorizer(on HTTP api) calls were going fine as long JWT is valid

## Steps to reproduce
Create a springboot 2 based AWS lambda with HTTP api and Authorization scope with scopes specified in it.

InputStream of call when Authorization scope is added contains a section with Scopes array but same is null when Authorization scope is not defined in JWT Authorizer in HTTP API

"scopes": [
"b",
"a",
"z",
"y",
"x"
]

InputStream of call when Authorization scope is not added

"scopes": null

## Full log output
*Paste the full log output from the Lambda function's CloudWatch logs*

```
logs
```

先重現透過 SAM 設定 Scopes、位於 HTTP API JWT authorizer 後方的 Spring Boot 2 AWS Lambda。讀取例外中指出的 AwsProxyRequest、AwsProxyRequestContext 和 ApiGatewayAuthorizerContext 位置，然後驗證 Scopes 的值為陣列以及為 null 時 invocation 都能成功。

由索引模型根據 Issue 內容生成。