helm executable extracted to temporary directory is globally writable.

### Bill of Materials or CLI Version

_No response_

### Execution Environment

JUnit Extensions

### Slf4j Logging Implementation

None

### To Reproduce

```markdown
Use helm client, inspect temporary directory with name such as `HelmSoftwareLoader4512790602684642253` containing globally writable helm executable.
```

### Describe the bug

`helm` executable is extracted as globally writable file.

### Describe the expected behavior

Extracted executable does not need to be writable, especially not be group or world.

### Whole JUnit/CLI Logs

```shell
N/A
```

### Additional Context

_No response_

Locate HelmSoftwareLoader and the code that extracts the helm executable into its temporary directory. Reproduce the extraction and inspect the resulting file permissions, then verify the fix with the relevant JUnit extension tests; done means the executable is not group- or world-writable.

由索引模型根据 Issue 内容生成。