Zipkin: Run health check through backend (#96031)

* Zipkin: Run health check through backend

* Mark some errors as downstream

* Update pkg/tsdb/zipkin/zipkin.go

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

* Use errors.New where error formatting is not needed

* Remove executable in plugin.json

* Fix joining the path

* Keep logger as global and then create from context

* Close the res body

---------

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

pkg/plugins/backendplugin/coreplugin/registry_test.go

@@ -35,6 +35,7 @@ func TestNewPlugin(t *testing.T) {
 		{ID: Tempo},
 		{ID: TestData, ExpectedAlias: TestDataAlias},
 		{ID: TestDataAlias, ExpectedID: TestData, ExpectedAlias: TestDataAlias},
+		{ID: Zipkin},
 	}
 
 	for _, tc := range tcs {