fix: custom endpoints with method: 'put' (#9037)

### What?
Fixes support for custom endpoints with `method: 'put'`.
Previously, this didn't work:
```ts
export default buildConfigWithDefaults({
  collections: [ ],
  endpoints: [
    {
      method: 'put',
      handler: () => new Response(),
      path: '/put',
    },
  ],
})
```

### Why?
We supported this in 2.0 and docs are saying that we can use `'put'` as
`method`
https://payloadcms.com/docs/beta/rest-api/overview#custom-endpoints

### How?
Implements the `REST_PUT` export for `@payloadcms/next/routes`, updates
all templates. Additionally, adds tests to ensure root/collection level
custom endpoints with all necessary methods execute properly.

Fixes https://github.com/payloadcms/payload/issues/8807

-->

test/helpers/NextRESTClient.ts

@@ -7,6 +7,7 @@ import {
   GRAPHQL_POST as createGraphqlPOST,
   REST_PATCH as createPATCH,
   REST_POST as createPOST,
+  REST_PUT as createPUT,
 } from '@payloadcms/next/routes'
 import * as qs from 'qs-esm'
 
@@ -67,6 +68,11 @@ export class NextRESTClient {
     args: { params: Promise<{ slug: string[] }> },
   ) => Promise<Response>
 
+  private _PUT: (
+    request: Request,
+    args: { params: Promise<{ slug: string[] }> },
+  ) => Promise<Response>
+
   private readonly config: SanitizedConfig
 
   private token: string
@@ -82,6 +88,7 @@ export class NextRESTClient {
     this._POST = createPOST(config)
     this._DELETE = createDELETE(config)
     this._PATCH = createPATCH(config)
+    this._PUT = createPUT(config)
     this._GRAPHQL_POST = createGraphqlPOST(config)
   }
 
@@ -221,4 +228,17 @@ export class NextRESTClient {
     })
     return this._POST(request, { params: Promise.resolve({ slug }) })
   }
+
+  async PUT(path: ValidPath, options: FileArg & RequestInit & RequestOptions): Promise<Response> {
+    const { slug, params, url } = this.generateRequestParts(path)
+    const { query, ...rest } = options
+    const queryParams = generateQueryString(query, params)
+
+    const request = new Request(`${url}${queryParams}`, {
+      ...rest,
+      headers: this.buildHeaders(options),
+      method: 'PUT',
+    })
+    return this._PUT(request, { params: Promise.resolve({ slug }) })
+  }
 }