Secrets: Move license check to secret store plugin (#53185)

* Move license check to secret store plugin

* Use shouldUseRemoteSecretsPlugin for migration

* Encapsulate plugin startup logic in sync.Once

* Remove global logger from startup functions

* Fix issues with wire and secrets plugin check

* Remove todo for plugin fatal error

* Rename fatalErr variable to be less confusing

* Fix merge conflicts

* Fix issue with grafana-cli wire and opentsdb

* Remove duplicated import on remote plugin

* Rename plugin check in favor of error return value

* Remove unnecessary import on grafana-cli wireexts_oss

* Remove unnecessary import on grafana wireexts_oss

* Reset sync.Once during test setup

* Remove unrelated opentsdb change on grafana-cli wire

* Readd opentsdb change on grafana-cli wire

pkg/api/frontendsettings.go

@@ -11,6 +11,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/datasources"
 	"github.com/grafana/grafana/pkg/services/licensing"
 	"github.com/grafana/grafana/pkg/services/pluginsettings"
+	"github.com/grafana/grafana/pkg/services/secrets/kvstore"
 	"github.com/grafana/grafana/pkg/setting"
 	"github.com/grafana/grafana/pkg/tsdb/grafanads"
 	"github.com/grafana/grafana/pkg/util"
@@ -87,6 +88,7 @@ func (hs *HTTPServer) getFrontendSettingsMap(c *models.ReqContext) (map[string]i
 	}
 
 	hasAccess := accesscontrol.HasAccess(hs.AccessControl, c)
+	secretsManagerPluginEnabled := kvstore.EvaluateRemoteSecretsPlugin(hs.secretsPluginManager, hs.Cfg) == nil
 
 	jsonObj := map[string]interface{}{
 		"defaultDatasource":                   defaultDS,
@@ -154,7 +156,7 @@ func (hs *HTTPServer) getFrontendSettingsMap(c *models.ReqContext) (map[string]i
 		"featureToggles":                   hs.Features.GetEnabled(c.Req.Context()),
 		"rendererAvailable":                hs.RenderService.IsAvailable(),
 		"rendererVersion":                  hs.RenderService.Version(),
-		"secretsManagerPluginEnabled":      hs.remoteSecretsCheck.ShouldUseRemoteSecretsPlugin(),
+		"secretsManagerPluginEnabled":      secretsManagerPluginEnabled,
 		"http2Enabled":                     hs.Cfg.Protocol == setting.HTTP2Scheme,
 		"sentry":                           hs.Cfg.Sentry,
 		"grafanaJavascriptAgent":           hs.Cfg.GrafanaJavascriptAgent,