Fix alert template parsing issue with '&g0.tab=1' not being stripped from URL params
Fixes issues relating to broken Grafana links in Slack alerts, see https://gitlab.slack.com/archives/C101F3796/p1718800992472389
- Fix alert template parsing issue that was accidentally introduced here !7487 (merged)
- Add alert template tests to give the ability of sense checking template rendering without needing to run an instance of Alertmanager
Edited by Taliesin Millhouse