JUPYTERHUB_OAUTH_SCOPES and JUPYTERHUB_OAUTH_ACCESS_SCOPES not correctly set with openpbs

Echoing out the `JUPYTERHUB_OAUTH_SCOPES` and `JUPYTERHUB_OAUTH_SCOPES` environment variables from JupyterHub jobs created by batchspawner, these values appear incorrect.

The current solution I'm using is noted in this issue:
https://github.com/jupyterhub/jupyterhub/issues/3866

I have the following in my `batch_script` section just before running the jupyterhub-singleuser component:

```
echo JUPYTERHUB_OAUTH_SCOPES "$JUPYTERHUB_OAUTH_SCOPES"
echo JUPYTERHUB_OAUTH_ACCESS_SCOPES "$JUPYTERHUB_OAUTH_ACCESS_SCOPES"

export JUPYTERHUB_OAUTH_SCOPES='["access:servers!server={username}/", "access:servers!user={username}"]'
export JUPYTERHUB_OAUTH_ACCESS_SCOPES='["access:servers!server={username}/", "access:servers!user={username}"]'

echo JUPYTERHUB_OAUTH_SCOPES "$JUPYTERHUB_OAUTH_SCOPES"
echo JUPYTERHUB_OAUTH_ACCESS_SCOPES "$JUPYTERHUB_OAUTH_ACCESS_SCOPES"
```

And it produces:
```
JUPYTERHUB_OAUTH_SCOPES [\access:servers!server=monsd/\, \access:servers!user=monsd\]
JUPYTERHUB_OAUTH_ACCESS_SCOPES [\access:servers!server=monsd/\, \access:servers!user=monsd\]

JUPYTERHUB_OAUTH_SCOPES ["access:servers!server=monsd/", "access:servers!user=monsd"]
JUPYTERHUB_OAUTH_ACCESS_SCOPES ["access:servers!server=monsd/", "access:servers!user=monsd"]
```

The top two lines are the default set by batchspawner, which then cause the resulting jupyterhub-singleuser instances to fail authentication. The bottom two are after I override them, and allow the instances to pass authentication and work.

Local instances of jupyterhub-singleuser, jupyter-server or JupyterLab all work fine. The problem only exists with batchspawner creating the jobs.

I'm using ProfileSpawner to build various launch profiles, and within that PBSSpawner via batchspawner.

`jupyterhub_config.py` snippet:

```
import batchspawner
c.JupyterHub.spawner_class = 'wrapspawner.ProfilesSpawner'
c.ProfilesSpawner.profiles = [
( 'Singularity /export/home/{username}/singularity/jupyterhub.sif', 'singularity_home_jupyter_cpu', 'batchspawner.PBSSpawner', dict(req_queue = 'workq', req_nprocs = '8', req_memory = '8gb', req_runtime = '1:00:00', batch_script = '''#!/bin/bash
#PBS -l walltime={runtime}
#PBS -l nodes=1:ppn={nprocs}
#PBS -l mem={memory}
#PBS -N jupyterhub
#PBS -v {keepvars}

echo JUPYTERHUB_OAUTH_SCOPES "$JUPYTERHUB_OAUTH_SCOPES"
echo JUPYTERHUB_OAUTH_ACCESS_SCOPES "$JUPYTERHUB_OAUTH_ACCESS_SCOPES"

export JUPYTERHUB_OAUTH_SCOPES='["access:servers!server={username}/", "access:servers!user={username}"]'
export JUPYTERHUB_OAUTH_ACCESS_SCOPES='["access:servers!server={username}/", "access:servers!user={username}"]'

echo JUPYTERHUB_OAUTH_SCOPES "$JUPYTERHUB_OAUTH_SCOPES"
echo JUPYTERHUB_OAUTH_ACCESS_SCOPES "$JUPYTERHUB_OAUTH_ACCESS_SCOPES"

singularity exec --bind /scratch /export/home/{username}/singularity/jupyterhub.sif {cmd}

''')),
```

Tested under both Python 3.10 and 3.12 with the following (batchspawner installed from main today).

```
batchspawner 1.3.0.dev0
jupyter_client 8.6.0
jupyter_core 5.7.1
jupyter-events 0.9.0
jupyter-lsp 2.2.3
jupyter_server 2.13.0
jupyter_server_terminals 0.5.2
jupyter-telemetry 0.1.0
jupyterhub 4.0.2
jupyterlab 4.1.2
jupyterlab_pygments 0.3.0
jupyterlab_server 2.25.3
tornado 6.4
traitlets 5.14.1
wrapspawner 1.0.1
```