disable router prefixing with pluginId (#44855) (#44908)

to unblock plugin migration until new api and static
resource services are available

Author: mshustov

src/core/server/plugins/plugin_context.ts

@@ -113,7 +113,7 @@ export function createPluginSetupContext<TPlugin, TPluginDependencies>(
         null,
         plugin.opaqueId
       ),
-      createRouter: () => deps.http.createRouter(`/${plugin.name}`, plugin.opaqueId),
+      createRouter: () => deps.http.createRouter('', plugin.opaqueId),
       registerOnPreAuth: deps.http.registerOnPreAuth,
       registerAuth: deps.http.registerAuth,
       registerOnPostAuth: deps.http.registerOnPostAuth,

test/plugin_functional/plugins/core_plugin_b/server/plugin.ts

@@ -29,7 +29,7 @@ declare module 'kibana/server' {
 export class CorePluginBPlugin implements Plugin {
   public setup(core: CoreSetup, deps: {}) {
     const router = core.http.createRouter();
-    router.get({ path: '/', validate: false }, async (context, req, res) => {
+    router.get({ path: '/core_plugin_b/', validate: false }, async (context, req, res) => {
       if (!context.pluginA) return res.internalError({ body: 'pluginA is disabled' });
       const response = await context.pluginA.ping();
       return res.ok({ body: `Pong via plugin A: ${response}` });