Fix Spark Connect container argumenets construction

### What happened?

Currently Spark Connect controller constructs container command and args with

```
container.Command = []string{"bash", "-c"}
args, err := buildStartConnectServerArgs(conn)
if err != nil {
return fmt.Errorf("failed to build spark connection args: %v", err)
}
container.Args = []string{strings.Join(args, " ")}
```

This is not ideal because everything is wrapped in `bash -c` which means all values passed in with the arg field are subject to shell interpretation.

We need to follow the way Spark Application Controller does it here: https://github.com/jayanth86/spark-operator/blob/00ba077967057560ad34949906d5ff4846659ce2/internal/controller/sparkapplication/submission.go#L71-L94

### Reproduction Code

_No response_

### Expected behavior

_No response_

### Actual behavior

_No response_

### Environment & Versions

- Kubernetes Version:
- Spark Operator Version:
- Apache Spark Version:

### Additional context

_No response_

### Impacted by this bug?

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Locate the Spark Connect controller code that calls buildStartConnectServerArgs and compare its container command and argument construction with internal/controller/sparkapplication/submission.go from the referenced commit. Confirm that arguments are passed without bash -c or shell joining, and run the relevant controller tests to verify Spark Connect startup still works.

Written by the indexing model from the issue text.