Migrate to Wire for dependency injection (#32289)

Fixes #30144

Co-authored-by: dsotirakis <sotirakis.dim@gmail.com>
Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>
Co-authored-by: Ida Furjesova <ida.furjesova@grafana.com>
Co-authored-by: Jack Westbrook <jack.westbrook@gmail.com>
Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>
Co-authored-by: Leon Sorokin <leeoniya@gmail.com>
Co-authored-by: Andrej Ocenas <mr.ocenas@gmail.com>
Co-authored-by: spinillos <selenepinillos@gmail.com>
Co-authored-by: Karl Persson <kalle.persson@grafana.com>
Co-authored-by: Leonard Gram <leo@xlson.com>

pkg/plugins/backendplugin/manager/manager_test.go

@@ -310,7 +310,7 @@ func TestManager(t *testing.T) {
 type managerScenarioCtx struct {
 	cfg     *setting.Cfg
 	license *testLicensingService
-	manager *manager
+	manager *Manager
 	factory backendplugin.PluginFactoryFunc
 	plugin  *testPlugin
 	env     []string
@@ -331,7 +331,7 @@ func newManagerScenario(t *testing.T, managed bool, fn func(t *testing.T, ctx *m
 	ctx := &managerScenarioCtx{
 		cfg:     cfg,
 		license: license,
-		manager: &manager{
+		manager: &Manager{
 			Cfg:                    cfg,
 			License:                license,
 			PluginRequestValidator: validator,
@@ -340,9 +340,6 @@ func newManagerScenario(t *testing.T, managed bool, fn func(t *testing.T, ctx *m
 		},
 	}
 
-	err := ctx.manager.Init()
-	require.NoError(t, err)
-
 	ctx.factory = func(pluginID string, logger log.Logger, env []string) (backendplugin.Plugin, error) {
 		ctx.plugin = &testPlugin{
 			pluginID: pluginID,