feat(medusa,framework,cli,admin-bundler): Integrate admin extensions into medusa build:plugin (#10941)

**What**
Calls the `plugin` script from `@medusajs/admin-bundler` as part of `medusa plugin:build`.

packages/medusa/src/commands/plugin/build.ts

@@ -1,12 +1,10 @@
-import { logger } from "@medusajs/framework/logger"
+import { plugin } from "@medusajs/admin-bundler"
 import { Compiler } from "@medusajs/framework/build-tools"
-
+import { logger } from "@medusajs/framework/logger"
 export default async function build({
   directory,
-  adminOnly,
 }: {
   directory: string
-  adminOnly: boolean
 }): Promise<boolean> {
   logger.info("Starting build...")
   const compiler = new Compiler(directory, logger)
@@ -18,5 +16,8 @@ export default async function build({
   }
 
   await compiler.buildPluginBackend(tsConfig)
+  await compiler.buildPluginAdminExtensions({
+    plugin,
+  })
   return true
 }