Fix Nil pointer when Deployment doesn't have 'last-applied-configuration'

Fix Nil pointer when Deployment doesn't have 'last-applied-configuration'

HPA and PDB validation improvements

1. In PRD, if HPA enabled, the minReplicas should higher than 3. And add an argument to ignore this check for corner case.
   PDB should check with Deployment + HPA,

2. Deployment replicas N or HPA minReplicas is N, and PDB has minAvailable is greater or equal than N, Block
   PDB has maxUnavailable 0