Plugins: Allow disabling "skip host environment variables" per-plugin (#78266)

* Plugins: Allow disabling skipping host environment variables per-plugin

* Renamed SkipEnvVarsDecorateFunc to SkipHostEnvVarsDecorateFunc

* PR review feedback

* fix tests

pkg/plugins/plugins.go

@@ -64,6 +64,8 @@ type Plugin struct {
 	client         backendplugin.Plugin
 	log            log.Logger
 
+	SkipHostEnvVars bool
+
 	mu sync.Mutex
 }