feat: add the user_connection_status_requested event model

[WilliamBergamin]

This pull request adds the user_connection_status_requested event model, so Bolt apps can register app.event(UserConnectionStatusRequestedEvent.class, ...).

• UserConnectionStatusRequestedEvent in slack-api-model, plus its handler and payload in slack-app-backend, following EntityDetailsRequestedEvent.
• Matches feat(types): add the user_connection_status_requested event node-slack-sdk#2783.

Testing

From an app with features.user_connections enabled and subscribed to the event:

app.event(UserConnectionStatusRequestedEvent.class, (payload, ctx) -> {
    ctx.client().appsUserConnectionUpdate(r -> r.userId(payload.getEvent().getUser()).status("disconnected"));
    return ctx.ack();
});

1. Open the app as a user without a recorded connection status and confirm the handler runs and the update succeeds.

Category (place an x in each of the [ ])

• bolt (Bolt for Java)
• bolt-{sub modules} (Bolt for Java - optional modules)
• slack-api-client (Slack API Clients)
• slack-api-model (Slack API Data Models)
• slack-api-*-kotlin-extension (Kotlin Extensions for Slack API Clients)
• slack-app-backend (The primitive layer of Bolt for Java)

Requirements

Please read the Contributing guidelines and Code of Conduct before creating this issue or pull request. By submitting, you agree to those rules.

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@383dd5f). Learn more about missing BASE report.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
.../handler/UserConnectionStatusRequestedHandler.java	0.00%	2 Missing ⚠️

Additional details and impacted files

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