guard function broken in theme folder

[guitaoliu]

Describe the bug

The guard function is broken by PR #436. Some checks expect the guard function to stop rendering if the first parameter value is false. After the change, as long as the value is not undefined, the component is always rendered. At least all required indication renderings are broken.

https://github.com/PaloAltoNetworks/docusaurus-openapi-docs/blob/main/packages/docusaurus-theme-openapi-docs/src/markdown/utils.ts#L27

Expected behavior

guard(false, () => <Test />) should stop rendering the Test component.

Screenshots