Plugins: Make it possible to support multiple plugin versions (#82116)

* first pass

* use version in more places

* add comment

* update installer

* fix wire

* fix tests

* tidy

* simplify changes

* fix in mem

* remove unused step

* fix step dupe logic for child plugins + add tests

pkg/services/pluginsintegration/pluginstore/store.go

@@ -18,6 +18,7 @@ var _ Store = (*Service)(nil)
 // Store is the publicly accessible storage for plugins.
 type Store interface {
 	// Plugin finds a plugin by its ID.
+	// Note: version is not required since Grafana only supports single versions of a plugin.
 	Plugin(ctx context.Context, pluginID string) (Plugin, bool)
 	// Plugins returns plugins by their requested type.
 	Plugins(ctx context.Context, pluginTypes ...plugins.Type) []Plugin
@@ -104,7 +105,7 @@ func (s *Service) SecretsManager(ctx context.Context) *plugins.Plugin {
 
 // plugin finds a plugin with `pluginID` from the registry that is not decommissioned
 func (s *Service) plugin(ctx context.Context, pluginID string) (*plugins.Plugin, bool) {
-	p, exists := s.pluginRegistry.Plugin(ctx, pluginID)
+	p, exists := s.pluginRegistry.Plugin(ctx, pluginID, "") // version is not required since Grafana only supports single versions of a plugin
 	if !exists {
 		return nil, false
 	}