Ensure Dashboard domain ID is set even when passed as a param

[christianwach]

Overview

Follows on from #15099 by fixing the identification of a Dashlet to update when domain_id is specified as a param when creating a Dashlet.

Before

When a Dashlet with name = 'blah' already exists, then attempting to create a new one with a different domain_id updates the existing one rather than creating a new Dashlet. This only occurs when domain_id is passed as a param.

// Construct params.
$params = array(
  'domain_id' => CRM_Core_Config::domainID(),
  'name' => 'blah',
  'label' => E::ts( 'Blah' ),
  'url' => 'civicrm/blah',
  'fullscreen_url' => 'civicrm/blah?context=dashletFullscreen',
  'permission' => 'access CiviCRM',
  'is_active' => 1,
  'cache_minutes' => 1,
);

// Create dashlet.
$dashlet = civicrm_api3( 'Dashboard', 'create', $params );

After

The code above correctly creates a Dashlet with the domain_id specified in the params.

[civibot]

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[seamuslee001]

Change makes sense to me merging