Image Rendering: Fix render of graph panel legend aligned to the right using Grafana image renderer plugin/service (#21854)

Don't render class body--phantomjs on body element when 
PhantomJS renderer not is in use.

Fixes #21830

packages/grafana-runtime/src/config.ts

@@ -67,6 +67,7 @@ export class GrafanaBootConfig {
     meta: false,
   };
   licenseInfo: LicenseInfo = {} as LicenseInfo;
+  phantomJSRenderer = false;
 
   constructor(options: GrafanaBootConfig) {
     this.theme = options.bootData.user.lightTheme ? getTheme(GrafanaThemeType.Light) : getTheme(GrafanaThemeType.Dark);