### What happened?

I'm sorry I didn't weigh in on #11277 before it was merged. I'm thinking of this specifically for how to get this properly consumed by the bindings as per #11443 

2 things to bring the grid code more in line with other endpoints.
1. Use POST if there is info to send to an endpoint instead of query string
2. Return payload needs to be nested inside a `value` key.

Current implementation of file endpoint is:
```
POST /session/:sessionId:/se/file
file: <zippedFile>
```

To minimize confusion, I think the new feature should use `files` instead of `file`:
```
POST /session/:sessionId:/se/files
{fileName: <filename>}
```
and for #11458 
```
GET /session/:sessionId:/se/files
```

### How can we reproduce the issue?

```shell
n/a
```


### Relevant log output

```shell
n/a
```


### Operating System

n/a

### Selenium version

trunk

### What are the browser(s) and version(s) where you see this issue?

n/a

### What are the browser driver(s) and version(s) where you see this issue?

n/a

### Are you using Selenium Grid?

trunk
private final int maxSessionCount;
  private final int configuredSessionCount;
  private final boolean cdpEnabled;
  private final String downloadsPath;
  private final boolean bidiEnabled;
  private final AtomicBoolean drainAfterSessions = new AtomicBoolean();
  private final List<SessionSlot> factories;
  private final Cache<SessionId, SessionSlot> currentSessions;
  private final Cache<SessionId, TemporaryFilesystem> tempFileSystems;
  private final AtomicInteger pendingSessions = new AtomicInteger();
  private final AtomicInteger sessionCount = new AtomicInteger();
  private LocalNode(
    Tracer tracer,
    EventBus bus,
    URI uri,
    URI gridUri,
    HealthCheck healthCheck,
    int maxSessionCount,
    int drainAfterSessionCount,
    boolean cdpEnabled,
    boolean bidiEnabled,
    Ticker ticker,
    Duration sessionTimeout,
    Duration heartbeatPeriod,
    List<SessionSlot> factories,
    Secret registrationSecret,
    String downloadsPath) {
    super(tracer, new NodeId(UUID.randomUUID()), uri, registrationSecret);
    this.bus = Require.nonNull("Event bus", bus);
    this.externalUri = Require.nonNull("Remote node URI", uri);