Runtime.HandlerNotFound Error when mountCode: true

I'm using localstack with a docker setup (localstrack-pro:latest), and when having `mountCode:true` in my plugin config the lambda container that is being spun up is unable to find the code. When disabled it executes fine but then code updates are not being propagated.

I added the fix of this pull request: #215 locally.
I'm also using `serverless-esbuild`.

serverless.yaml

```yaml
service: cms-api
configValidationMode: error

provider:
stackName: ${env:STACK_NAME, 'serverless-framework'}-sls-middleware
name: aws
runtime: nodejs18.x
stage: local
region: ${env:AWS_DEFAULT_REGION, 'eu-central-1'}
environment: ${file(./serverless.yml):provider.environment}
apiGateway:
binaryMediaTypes:
- '*/*'
restApiId: !Ref ApiGateway
restApiRootResourceId:
'Fn::GetAtt':
- ApiGateway
- RootResourceId

plugins:
- serverless-esbuild
- serverless-localstack

custom:
stage: local
esbuild:
bundle: true
minify: false
keepOutputDirectory: true
outputFileExtension: .mjs
format: esm
target: "esnext"
platform: "node"
exclude: ["aws-sdk"]
banner:
js: import { createRequire } from 'module';const require = createRequire(import.meta.url);
localstack:
debug: true
edgePort: 4566
autostart: false
stages: [ local ]
lambda:
mountCode: true

functions:
api: ${file(./serverless.yml):functions.api}

resources:
Resources:
DynamoDBTableCMS: ${file(./serverless.yml):resources.Resources.DynamoDBTableCMS}
ApiGateway:
Type: AWS::ApiGateway::RestApi
Properties:
Name: ApiGateway
Tags:
- Key: _custom_id_
Value: cms-api
```

docker-compose.yaml

```yaml
version: "3"
services:
localstack:
container_name: "api-localstack"
build:
context: ./docker/localstack
ports:
- "127.0.0.1:4566:4566" # LocalStack Gateway
- "127.0.0.1:4510-4559:4510-4559" # external services port range
- "127.0.0.1:53:53" # DNS config (only required for Pro)
- "127.0.0.1:53:53/udp" # DNS config (only required for Pro)
- "127.0.0.1:443:443" # LocalStack HTTPS Gateway (only required for Pro)
working_dir: /
environment:
- SERVICES=lambda,s3,sqs,iam,apigateway,dynamodb # SERVICES variable is ignored if EAGER_SERVICE_LOADING=0
- LS_LOG=debug
- PERSISTENCE=1
- BUCKET_MARKER_LOCAL=hot-reload
- LOCALSTACK_API_KEY={redacted} # only required for Pro
- DOCKER_HOST=unix:///var/run/docker.sock
- STACK_NAME=api
- ENVIRONMENT=local
- DYNAMODB_SHARE_DB=1

volumes:
- "./docker/localstack/volume:/var/lib/localstack"
- "/var/run/docker.sock:/var/run/docker.sock"
- "./:/app"
```

When the errors happens it keeps re spawning the lambda container until I stop it.
Logs

**api-localstack** | 2023-03-31T08:56:57.475 DEBUG --- [pi:$LATEST_0] l.u.c.docker_sdk_client : Creating container with attributes: {'mount_volumes': , 'ports': None, 'cap_add': None, 'cap_drop': None, 'security_opt': None, 'dns': '127.0.0.1', 'additional_flags': '', 'workdir': None, 'privileged': None, 'labels': None, 'ulimits': None, 'command': None, 'detach': None, 'entrypoint': '/var/rapid/init', 'env_vars': {'AWS_DEFAULT_REGION': 'us-east-1', 'AWS_REGION': 'us-east-1', 'AWS_LAMBDA_FUNCTION_NAME': 'api-local-api', 'AWS_LAMBDA_FUNCTION_MEMORY_SIZE': 1024, 'AWS_LAMBDA_FUNCTION_VERSION': '$LATEST', 'AWS_LAMBDA_INITIALIZATION_TYPE': 'on-demand', 'AWS_LAMBDA_LOG_GROUP_NAME': '/aws/lambda/api-local-api', 'AWS_LAMBDA_LOG_STREAM_NAME': '2023/03/31/[$LATEST]0af9cbe7a820c0ba0db5030e64e1a184', 'AWS_ACCESS_KEY_ID': 'ASIAQAAAAAAADD2Y7UJJ', 'AWS_SECRET_ACCESS_KEY': 'yKdyaQMgFPFCyBv4nPtbiWaYIjrsvq3cV1gPFSl8', 'AWS_SESSION_TOKEN': 'FQoGZXIvYXdzEBYaD/DkcwdRjXJnysJVWiDvT8it86Tfw38AdeGKjio0Af69yx/ZcohR60kbG1Gu07EkxZO/j/s864mi/lgO5ktQrb4XVSn5GlB7gAU4Q2JOmlVCTaTXcnAvbix42UMVfkOfKHp6Prvl9yxB2aPqoy8Z2hXrr3vRAHcWwE9rFYVXn7lTDSCBfb8rLyB19Qfrhnqn35yK4URyJVgVsjHzqp0EtZvxOgSirgSo7U9OJRH/c4luhx3BxOcfyqBKKf3zxRILTx1z8VAT4QTfs7zhMJwpo+1AqWeYByodRP7XUtlRCLwts6nqdlomBDq7DzYdjJSRjSbpgRREFJGMxkDD3xE=', 'LAMBDA_TASK_ROOT': '/var/task', 'LAMBDA_RUNTIME_DIR': '/var/runtime', 'AWS_XRAY_CONTEXT_MISSING': 'LOG_ERROR', 'AWS_XRAY_DAEMON_ADDRESS': '127.0.0.1:2000', '_AWS_XRAY_DAEMON_PORT': '2000', '_AWS_XRAY_DAEMON_ADDRESS': '127.0.0.1', 'TZ': ':UTC', 'AWS_LAMBDA_FUNCTION_TIMEOUT': 6, 'LOCALSTACK_HOSTNAME': '172.30.0.2', 'EDGE_PORT': '443', 'AWS_ENDPOINT_URL': 'http://172.30.0.2:443', 'LOCALSTACK_RUNTIME_ID': '0af9cbe7a820c0ba0db5030e64e1a184', 'LOCALSTACK_RUNTIME_ENDPOINT': 'http://172.30.0.2:443/_localstack_lambda/0af9cbe7a820c0ba0db5030e64e1a184', '_HANDLER': '.esbuild/.build/src/handler/http.handle', 'AWS_EXECUTION_ENV': 'Aws_Lambda_nodejs18.x', 'ENVIRONMENT': 'local', 'LOCALSTACK_HOT_RELOADING_PATHS': '/var/task', 'LOCALSTACK_ENABLE_DNS_SERVER': '1', 'NODE_TLS_REJECT_UNAUTHORIZED': '0'}, 'image_name': 'public.ecr.aws/lambda/nodejs:18', 'interactive': None, 'name': 'api-localstack-lambda-api-local-api-0af9cbe7a820c0ba0db5030e64e1a184', 'network': 'cms_api_default', 'platform': 'linux/amd64', 'remove': None, 'self': , 'tty': None, 'user': None}
**api-localstack** | 2023-03-31T08:56:57.518 DEBUG --- [pi:$LATEST_0] localstack.packages.api : Installation of awslambda-runtime skipped (already installed).
**api-localstack** | 2023-03-31T08:56:57.518 DEBUG --- [pi:$LATEST_0] l.u.c.docker_sdk_client : Copying file /var/lib/localstack/lib/awslambda-runtime/v0.1.16-pre/x86_64/. into api-localstack-lambda-api-local-api-0af9cbe7a820c0ba0db5030e64e1a184:/
**api-localstack** | 2023-03-31T08:56:57.824 DEBUG --- [pi:$LATEST_0] l.u.c.docker_sdk_client : Starting container api-localstack-lambda-api-local-api-0af9cbe7a820c0ba0db5030e64e1a184
**api-localstack** | 2023-03-31T08:56:57.827 DEBUG --- [ asgi_gw_0] l.u.c.docker_sdk_client : Removing container: api-localstack-lambda-api-local-api-9de9563801ea86a2fc7cb199626b3200
**api-localstack** | 2023-03-31T08:56:57.946 INFO --- [ asgi_gw_0] localstack.request.http : POST /_localstack_lambda/9de9563801ea86a2fc7cb199626b3200/status/9de9563801ea86a2fc7cb199626b3200/error => 202
**api-localstack** | 2023-03-31T08:56:58.250 DEBUG --- [pi:$LATEST_0] l.u.c.container_client : Getting ipv4 address for container api-localstack-lambda-api-local-api-0af9cbe7a820c0ba0db5030e64e1a184 in network cms_api_default.
**api-localstack** | 2023-03-31T08:56:58.421 WARN --- [ asgi_gw_0] l.s.a.i.executor_endpoint : Execution environment startup failed: {"errorType":"Runtime.HandlerNotFound","errorMessage":".esbuild/.build/src/handler/http.handle is undefined or not exported","trace":["Runtime.HandlerNotFound: .esbuild/.build/src/handler/http.handle is undefined or not exported"," at UserFunction.js.module.exports.load (file:///var/runtime/index.mjs:1035:15)"," at async start (file:///var/runtime/index.mjs:1195:23)"," at async file:///var/runtime/index.mjs:1201:1"]}
**api-localstack** | 2023-03-31T08:56:58.421 DEBUG --- [ asgi_gw_0] l.u.c.docker_sdk_client : Stopping container: api-localstack-lambda-api-local-api-0af9cbe7a820c0ba0db5030e64e1a184

Screenshot of the built code:

Screenshot of the lambda on app.localstack.cloud (this is with mountCode: false)

Screenshot of the lambda on app.localstack.cloud ( this is with mountCode: true)

Start by reviewing pull request #215 and the mountCode path used with serverless-esbuild, then reproduce the issue with the provided serverless.yaml and docker-compose.yaml. Use the logged Runtime.HandlerNotFound failure to trace why the mounted handler is unavailable. Done means mountCode:true starts the Lambda successfully and code updates are propagated.

Written by the indexing model from the issue text.