Merge pull request #122 from newfold-labs/fix/fatal-with-no-capabilit…

…ies-PRESS10-107

Ensure `all` method returns an empty array if capabilities are not available

includes/SiteCapabilities.php

@@ -57,7 +57,7 @@ public function all(): array {
 			$this->transient->set( 'nfd_site_capabilities', $capabilities, 4 * constant( 'HOUR_IN_SECONDS' ) );
 		}
 
-		return $capabilities;
+		return is_array( $capabilities ) ? $capabilities : array();
 	}
 
 	/**