[v1.4.2] Deprecation warning with PHP 8: http_build_query

[log1-c]

In case someone stumbles over this:

This is just for quickly fixing the deprecation message you get with Version 1.4.2 of the module together with PHP 8:
(master branch/IcingaDB version of the module already have that fix)

Deprecated: http_build_query(): Passing null to parameter #2 ($numeric_prefix) of type string is deprecated in /usr/share/icingaweb2/modules/grafana/library/Grafana/Helpers/Timeranges.php on line 95

To fix this change line 95 to

['url' => 'grafana/dashboard?' . http_build_query($this->urlparams, '', '&', PHP_QUERY_RFC3986)],