Plugins: Track plugin signing errors and expose them to the frontend (#28219)

* first pass

* return list

* types and cleanup

* add to plugin page and add styles

* update comment

* update comment

* fix component path

* simplify error component

* simplify error struct

* fix tests

* don't export and fix string()

* update naming

* remove frontend

* introduce phantom loader

* track single error

* remove error from base

* remove unused struct

* remove unnecessary filter

* add errors endpoint

* Update set log to use id field

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* skip adding BE plugins

* remove errs from plugin + ds list

* remove unnecessary fields

* add signature state to panels

* remove unused code

* apply PR feedback

* update comment

* merge dto with model

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/api/plugins.go

@@ -121,7 +121,7 @@ func (hs *HTTPServer) GetPluginList(c *models.ReqContext) Response {
 			listItem.DefaultNavUrl = setting.AppSubUrl + "/plugins/" + listItem.Id + "/"
 		}
 
-		// filter out disabled
+		// filter out disabled plugins
 		if enabledFilter == "1" && !listItem.Enabled {
 			continue
 		}
@@ -364,6 +364,10 @@ func (hs *HTTPServer) getCachedPluginSettings(pluginID string, user *models.Sign
 	return query.Result, nil
 }
 
+func (hs *HTTPServer) GetPluginErrorsList(c *models.ReqContext) Response {
+	return JSON(200, plugins.ScanningErrors())
+}
+
 func translatePluginRequestErrorToAPIError(err error) Response {
 	if errors.Is(err, backendplugin.ErrPluginNotRegistered) {
 		return Error(404, "Plugin not found", err)