[Refactor][kubectl-plugin] Share common struct for cluster-related CLI options to reduce duplication

[CheyuWu]

Why are these changes needed?

Currently, both SubmitJobOptions and CreateWorkerGroupOptions structs contain many overlapping fields related to Ray cluster configuration, such as resource specs (CPU, GPU, memory), image, version, and selectors.

Maintaining these separately leads to duplicated code and increases the risk of inconsistency when updating argument definitions.

• Create a struct KubectlPluginCommonOptions in kubectl-plugin/pkg/util/types.go
• Extract the common part of SubmitJobOptions and CreateWorkerGroupOptions.

The following element has been moved to kubectl-plugin/pkg/util/types.go

- CmdFactory          cmdutil.Factory
- IoStreams           *genericiooptions.IOStreams
- Namespace           string
- WorkerNodeSelectors map[string]string
- RayVersion          string
- WorkerCPU           string
- WorkerGPU           string
- WorkerMemory        string
- WorkerReplicas      int32

Related issue number

Closes #3582

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(