Enabling "Include Source" in Custom macOS Unified Logs Integration Causes Agent Failure #47296

Description

When configuring the Custom macOS Unified Logs integration, enabling the Include source toggle causes the Elastic Agent input to fail with a decoding error.
This happens whether Include source is enabled alone or together with other toggles.

Steps to Reproduce

1. Go to Integrations -> Custom macOS Unified Logs.
2. Create or edit an existing integration policy.
3. Set a valid predicate in Predicate parameter.,
4. Leave other fields as default.
5. Enable the Include source toggle (alone or along with other toggles).
6. Save the integration and observe the agent status under Fleet -> Agents.

Expected Behavior

The integration should successfully collect macOS unified logs even when Include source is enabled.

Actual Behavior

• The Elastic Agent becomes Unhealthy.
• The integration shows a Failed state with the following error message:

decoding error: decoding failed due to the following error(s):
'streams[0].source' expected a map or struct, got "bool"

Environment Details

• Elastic Agent version: 9.1.5
• Integration: Custom macOS Unified Logs
• Host OS: macOS (Elastic Agent locally installed)

Working configuration

• All toggles disabled, or
• All toggles enabled except Include source.

Failing configuration

• Include source enabled (alone or along with other toggles).

Screenshots