Chore: pass url parameters through context.Context (#38826)

* pass url parameters through context.Context

* fix url param names without colon prefix

* change context params to vars

* replace url vars in tests using new api

* rename vars to params

* add some comments

* rename seturlvars to seturlparams

pkg/services/ngalert/api/api_alertmanager.go

@@ -17,6 +17,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/ngalert/notifier"
 	"github.com/grafana/grafana/pkg/services/ngalert/store"
 	"github.com/grafana/grafana/pkg/util"
+	"gopkg.in/macaron.v1"
 )
 
 const (
@@ -154,7 +155,7 @@ func (srv AlertmanagerSrv) RouteDeleteSilence(c *models.ReqContext) response.Res
 		return errResp
 	}
 
-	silenceID := c.Params(":SilenceId")
+	silenceID := macaron.Params(c.Req)[":SilenceId"]
 	if err := am.DeleteSilence(silenceID); err != nil {
 		if errors.Is(err, notifier.ErrSilenceNotFound) {
 			return ErrResp(http.StatusNotFound, err, "")
@@ -281,7 +282,7 @@ func (srv AlertmanagerSrv) RouteGetSilence(c *models.ReqContext) response.Respon
 		return errResp
 	}
 
-	silenceID := c.Params(":SilenceId")
+	silenceID := macaron.Params(c.Req)[":SilenceId"]
 	gettableSilence, err := am.GetSilence(silenceID)
 	if err != nil {
 		if errors.Is(err, notifier.ErrSilenceNotFound) {