Automatic merge from submit-queue (batch tested with PRs 51244, 50559, 49770, 51194, 50901)
Fix zsh completion for kubeadm
**What this PR does / why we need it**:
kubeadm zsh completion will report an error when using after '--flag':
```
kubeadm join --token=1 __handle_flag:25: bad math expression: operand expected at end of string
```
There is a similar bug in kubectl which has been fixed by #48553. It is due to `__kubeadm_declare` gets 'declare -A' into function scope, and `__kubeadm_declare` could be removed now.
This is to port that fix here.
**Which issue this PR fixes**
**Special notes for your reviewer**:
**Release note**:
16fee22953