Merge pull request #53751 from jingax10/kube_up_branch

Automatic merge from submit-queue (batch tested with PRs 53604, 53751). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Minior fix on getting subnet mode by gcloud

**What this PR does / why we need it**:

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:
Tested kube-up.sh & kube-down.sh locally. env PREEXISTING_NETWORK_MODE is assigned with the expected mode and "WARNING: Argument NAME is deprecated. Use --filter="name=( 'NAME' ... )" instead." goes away.


**Release note**:

```release-note
NONE
```

Author: Kubernetes Submit Queue