Sandbox process continues emitting logs to `boot` logs after sandbox has booted and user container has started

### Description

I was digging through some logs today and noticed that the gofer doesn't seem to be respecting the `--debug-command boot,create` option the way the sandbox does. It continues to emit debug logs well after the sentry has completed the create and boot steps and this causes a lot of noise when it's not expected that it should keep logging. I've made a change to our runtime to stop forwarding these logs after gvisor has started the guest process but I wasn't sure if it was intended that the gofer continue writing debug logs. I tried adding `!gofer` to the list but it didn't seem to have an effect on the output. Also, gvisor continues to print `Time: Adjusting syscall overhead down to 7` the entire time as well, even after boot, so that's another component that doesn't seem to respect the debug command filters.

Note that we still have directfs disabled, as the performance benefits are not relevant to our workloads.

### Steps to reproduce

1. Install gvisor runtime with debug options limited to `--debug-command=boot,create` and `--directfs=false`
2. Run a docker container and do some I/O
3. Inspect the debug logs and see that gofer still prints debug logs and the sampler continues printing debug logs as well

### runsc version

```shell
`release-20241021.0`
```

### docker version (if using docker)

```shell

```

### uname

_No response_

### kubectl (if using Kubernetes)

```shell

```

### repo state (if built from source)

_No response_

### runsc debug logs (if available)

```shell

```