FST[Infra] In WorkloadReplicas getComponentByType() should allow one component of a given type

### Bill of Materials or CLI Version

_No response_

### Execution Environment

JUnit Extensions

### Slf4j Logging Implementation

None

### To Reproduce

```markdown
na
```

### Describe the bug

In com.hedera.fullstack.infrastructure.api.model.WorkloadReplicas

" return (C) components.stream()
.filter(componentType::isInstance)
.findFirst()
.get();
"

Comment s by @[nathanklick]

Is this behavior correct to only return the first component of the given type even if there are multiple matches? Should we permit multiple components of the same type within a single workload replica?

### Describe the expected behavior

multiple components of the same type workload replica should not be permitted

### Whole JUnit/CLI Logs

```shell
na
```

### Additional Context

_No response_

Start with com.hedera.fullstack.infrastructure.api.model.WorkloadReplicas and its getComponentByType() method, then inspect how components are added to a workload replica. Confirm how duplicate component types are represented and define the expected single-component behavior; done means coverage verifies that multiple components of the same type are not permitted.

Written by the indexing model from the issue text.