fix: add maxDelay to prevent exponential backoff in waiters

[EzgiTastan]

Issue #, if available:
N/A (new issue discovered)

Description of changes:

Problem

The SDK v3 upgrade (commits a15de3c, b5c6c3f) added minDelay but did not add maxDelay to the waiter options. Without maxDelay, the AWS SDK defaults to 120 seconds, causing exponential backoff between polls:

Poll #	Delay
1	15s
2	~30s
3	~60s
4+	120s

This means even if the ECS service becomes stable quickly, the action may wait up to 2 minutes before the next poll detects it.

Solution

Added maxDelay: WAIT_DEFAULT_DELAY_SEC (15 seconds) to all three waiters:

• waitUntilTasksStopped
• waitUntilServicesStable
• waitUntilDeploymentSuccessful

This ensures consistent 15-second polling intervals without exponential backoff.

Testing

• All 45 existing tests pass
• Rebuilt dist/index.js with npm run package

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