Automatic merge from submit-queue (batch tested with PRs 55839, 54495, 55884, 55983, 56069). 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>.
Add condition "len(cfg.DiscoveryToken) != 0" to ValidateArgSelection.
**What this PR does / why we need it**:
as per https://github.com/kubernetes/kubernetes/pull/54982#discussion_r149968848
>only when the conditions having len(cfg.DiscoveryToken) != 0 means "using token-based discovery" as is mentioned in the error message.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
ref: #54982
**Special notes for your reviewer**:
/cc @kubernetes/sig-cluster-lifecycle-pr-reviews
**Release note**:
```release-note
NONE
```
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