CustomResourceConfig: addLogRetentionLifetime doesn't work with 2 AwsCustomResources

### Describe the bug

CustomResourceConfig.addLogRetentionLifetime() fails at synth-time if I have 2 AwsCustomResources in the stack with:
```
There is already a Construct with name 'logGroup' in CfnFunction [Resource]
```

Works, if there's only 1 AwsCustomResource.

### Regression Issue

- [ ] Select this option if this issue appears to be a regression.

### Last Known Working CDK Library Version

_No response_

### Expected Behavior

No exception

### Current Behavior

```
Exception in thread "main" java.lang.RuntimeException: Error: There is already a Construct with name 'logGroup' in CfnFunction [Resource]
@jsii/kernel.RuntimeError: Error: There is already a Construct with name 'logGroup' in CfnFunction [Resource]
at Kernel._Kernel_ensureSync (/private/var/folders/2f/7cf6g_yj5x10vq_3zclbb72h0000gn/T/jsii-java-runtime17928144539978102170/lib/program.js:927:23)
at Kernel.invoke (/private/var/folders/2f/7cf6g_yj5x10vq_3zclbb72h0000gn/T/jsii-java-runtime17928144539978102170/lib/program.js:294:102)
at KernelHost.processRequest (/private/var/folders/2f/7cf6g_yj5x10vq_3zclbb72h0000gn/T/jsii-java-runtime17928144539978102170/lib/program.js:15467:36)
at KernelHost.run (/private/var/folders/2f/7cf6g_yj5x10vq_3zclbb72h0000gn/T/jsii-java-runtime17928144539978102170/lib/program.js:15427:22)
at Immediate._onImmediate (/private/var/folders/2f/7cf6g_yj5x10vq_3zclbb72h0000gn/T/jsii-java-runtime17928144539978102170/lib/program.js:15428:46)
at process.processImmediate (node:internal/timers:505:21)
at software.amazon.jsii.JsiiRuntime.processErrorResponse(JsiiRuntime.java:147)
at software.amazon.jsii.JsiiRuntime.requestResponse(JsiiRuntime.java:116)
at software.amazon.jsii.JsiiClient.callMethod(JsiiClient.java:184)
at software.amazon.jsii.Kernel.call(Kernel.java:52)
at software.amazon.awscdk.Stage.synth(Stage.java:108)
at com.cartelsol.spike.aws.customresource.infra.CustomResourceMain.main(CustomResourceMain.kt:38)
```

### Reproduction Steps

```
object CustomResourceMain {

@JvmStatic
fun main(vararg args: String) {
val app = App()

val stack = Stack.Builder.create(app, "MyStack")
.stackName("TestStack")
.env(Environment.builder().account("ACCOUNT_ID").region("eu-central-1").build())
.build()

AwsCustomResource.Builder.create(stack, "AwsCustomResource1")
.onCreate(AwsSdkCall.builder().service("Iot").action("describeEndpoint").physicalResourceId(PhysicalResourceId.of("ID1")).build())
.policy(AwsCustomResourcePolicy.fromSdkCalls(SdkCallsPolicyOptions.builder().resources(AwsCustomResourcePolicy.ANY_RESOURCE).build()))
.build()

AwsCustomResource.Builder.create(stack, "AwsCustomResource2")
.onCreate(AwsSdkCall.builder().service("Iot").action("describeEndpoint").physicalResourceId(PhysicalResourceId.of("ID2")).build())
.policy(AwsCustomResourcePolicy.fromSdkCalls(SdkCallsPolicyOptions.builder().resources(AwsCustomResourcePolicy.ANY_RESOURCE).build()))
.build()

CustomResourceConfig.of(app).addLogRetentionLifetime(RetentionDays.TEN_YEARS)

app.synth()
}
}
```

### Possible Solution

_No response_

### Additional Information/Context

_No response_

### AWS CDK Library version (aws-cdk-lib)

2.195.0

### AWS CDK CLI version

2.1014.0

### Node.js Version

22.15.1

### OS

MacOS

### Language

Java

### Language Version

21

### Other information

_No response_

Start by running the Kotlin reproduction with two AwsCustomResources and CustomResourceConfig.of(app).addLogRetentionLifetime(), then inspect the implementation of CustomResourceConfig and AwsCustomResource around app.synth(). Done means synthesis succeeds with both resources and a regression test confirms that no duplicate 'logGroup' construct error occurs.

Written by the indexing model from the issue text.