Fix OOM in awssqs-event-queue test JVM

## Bug Description

CI builds fail in the `conductor-awssqs-event-queue` module with:

```
java.lang.OutOfMemoryError: Java heap space
SQSObservableQueueTest > testPolicyJsonFormat FAILED
```

The default test JVM heap is insufficient for `testPolicyJsonFormat`. The failure is isolated to this module and blocks pipeline runs.

## Fix

Increase test JVM heap size in `awssqs-event-queue/build.gradle` for the test task.

## Affected File

- `awssqs-event-queue/build.gradle`

## Prior Art

Community PR #697 by @ivakoleva addressed this with a targeted heap increase (6 additions). Fix was validated locally and stabilized the build pipeline.

Start with awssqs-event-queue/build.gradle and the SQSObservableQueueTest testPolicyJsonFormat failure described in the issue. Run the module's test task to reproduce the heap error, then verify that the targeted test completes without an OutOfMemoryError and the module tests pass.

Written by the indexing model from the issue text.