aws-ec2: ec2.InitFile.fromObject generates a JSON file with properties converted to string

### Describe the bug

When creating files in an EC2 instance during CloudFormation Init, if using `ec2.InitFile.fromObject()`, than the JSON fields are converted to string. For example, the object
```JSON
{
"integer": 10,
"string": "eleven",
"decimal": 12.12,
"boolean": true,
"array": [1, "two", 3.3, false]
}
```

Is converted to
```JSON
{
"integer": "10",
"string": "eleven",
"decimal": "12.12",
"boolean": "true",
"array": ["1", "two", "3.3", "false"]
}
```

### Expected Behavior

File content generated by `ec2.InitFile.fromObject()` to be similar to:
```{"integer":10,"string":"eleven","decimal":12.12,"boolean":true,"array":[1,"two",3.3,false]}```

### Current Behavior

File content is like:
```{"boolean": "true", "string": "eleven", "integer": "10", "array": ["1", "two", "3.3", "false"], "decimal": "12.12"}```

### Reproduction Steps

In a new CDK project (initialized with `cdk init app --language typescript`):

```
#!/usr/bin/env node
import "source-map-support/register";
import { Construct } from "constructs";
import * as cdk from "aws-cdk-lib";
import * as ec2 from "aws-cdk-lib/aws-ec2";

class InstanceStack extends cdk.Stack {
constructor(scope: Construct, id: string, props?: cdk.StackProps) {
super(scope, id, props);

const vpc = ec2.Vpc.fromLookup(this, "VPC", {
isDefault: true,
});

const jsonFile = {
integer: 10,
string: "eleven",
decimal: 12.12,
boolean: true,
array: [1, "two", 3.3, false],
};

new ec2.Instance(this, "Instance", {
vpc,
instanceType: new ec2.InstanceType("t3.nano"),
machineImage: ec2.MachineImage.latestAmazonLinux2(),
init: ec2.CloudFormationInit.fromElements(
ec2.InitFile.fromObject("/tmp/first.json", jsonFile),
ec2.InitFile.fromString("/tmp/second.json", JSON.stringify(jsonFile))
),
});
}
}

const app = new cdk.App();
new InstanceStack(app, "InstanceStack", {
env: {
account: process.env.CDK_DEFAULT_ACCOUNT,
region: process.env.CDK_DEFAULT_REGION,
},
});
```

### Possible Solution

_No response_

### Additional Information/Context

Here are the files section of the generated template

JSON
```JSON
"files": {
"/var/first.json": {
"content": {
"integer": 10,
"string": "eleven",
"decimal": 12.12,
"boolean": true,
"arary": [1, "two", 3.3, false]
},
"mode": "000644",
"owner": "root",
"group": "root"
},
"/var/second.json": {
"content": "{\"integer\":10,\"string\":\"eleven\",\"decimal\":12.12,\"boolean\":true,\"array\":[1,\"two\",3.3,false]}",
"encoding": "plain",
"mode": "000644",
"owner": "root",
"group": "root"
}
}
```

YAML
```YAML
files:
/var/first.json:
content:
integer: 10
string: eleven
decimal: 12.12
boolean: true
array:
- 1
- two
- 3.3
- false
mode: '000644'
owner: root
group: root
/var/second.json:
content: >-
{"integer":10,"string":"eleven","decimal":12.12,"boolean":true,"array":[1,"two",3.3,false]}
encoding: plain
mode: '000644'
owner: root
group: root
```

And here is the content of `/var/lib/cfn-init/data/metadata.json` in the instance:
```JSON
{
"AWS::CloudFormation::Init": {
"configSets": {
"default": [
"config"
]
},
"config": {
"files": {
"/var/first.json": {
"mode": "000644",
"owner": "root",
"content": {
"boolean": "true",
"string": "eleven",
"array": [
"1",
"two",
"3.3",
"false"
],
"integer": "10",
"decimal": "12.12"
},
"group": "root"
},
"/var/second.json": {
"mode": "000644",
"owner": "root",
"encoding": "plain",
"content": "{\"integer\":10,\"string\":\"eleven\",\"decimal\":12.12,\"boolean\":true,\"array\":[1,\"two\",3.3,false]}",
"group": "root"
}
}
}
},
"aws:cdk:path": "InstanceStack/Instance/Resource"
}
```

### CDK CLI Version

2.117.0

### Framework Version

2.117.0

### Node.js Version

20.2.0

### OS

Windows 11

### Language

TypeScript

### Language Version

5.3.3

### Other information

There is an older issue [here](https://github.com/aws/aws-cdk/issues/14100) for the same issue, but even though it was closed, I can still reproduce the issue in 2.117.0.

Start at ec2.InitFile.fromObject and compare its generated CloudFormation Init metadata with the fromString example in the reproduction. Verify the resulting /var/first.json content preserves numeric, boolean, and array element types, using the issue's expected JSON as the completion criterion.

Written by the indexing model from the issue text.