fix(public-toc): show the author's name instead of the raw creator username

[likhithThammegowda]

The public course overview showed the internal creator username — creatorjhpaastrika_0qfj — where the signed-in course page shows Jhpiego Cooperation. It now shows the same name. Release notes for 4.2.11 ride along on this branch.

Why it isn't a one-line copy

The signed-in TOC renders content?.content?.creatorDetails[0]?.name. Copying that expression here would have rendered nothing.

That expression only works there because app-toc-home parses the field first:

if (this.checkJson(data.content.data.creatorDetails)) {
  data.content.data.creatorDetails = JSON.parse(data.content.data.creatorDetails)
}

The public page is fed by the public search API, which returns creatorDetails as a JSON string. Verified against the live payload for do_1146265657225789441402:

typeof: string
raw:    "[{\"id\":\"28ec6b71…\",\"name\":\"Jhpiego Cooperation\"}]"
naive creatorDetails[0]?.name  →  undefined       ("[" has no .name)

The content service returns the same field already parsed, so the getter handles both shapes and falls back to creator when the details are malformed or absent — it can never render less than before.

Verification

• Production build green (yarn run build:local, exit 0)
• public-toc-banner.component.spec.ts 13/13, including 7 new cases covering both payload shapes plus malformed, absent, no-name and null-content
• Confirmed on the running app before release

Risk

Low. Confined to the public course overview banner and fallback-guarded, so the worst case is the previous behaviour.