Plugins: Track plugin signing errors and expose them to the frontend (#28219) (#28505)

* 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>
(cherry picked from commit 1bee9f4168)

Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>

pkg/api/api.go

@@ -256,6 +256,7 @@ func (hs *HTTPServer) registerRoutes() {
 		apiRoute.Get("/plugins/:pluginId/health", Wrap(hs.CheckHealth))
 		apiRoute.Any("/plugins/:pluginId/resources", hs.CallResource)
 		apiRoute.Any("/plugins/:pluginId/resources/*", hs.CallResource)
+		apiRoute.Any("/plugins/errors", Wrap(hs.GetPluginErrorsList))
 
 		apiRoute.Group("/plugins", func(pluginRoute routing.RouteRegister) {
 			pluginRoute.Get("/:pluginId/dashboards/", Wrap(GetPluginDashboards))