fix: resolve unreachable code and infinite loop in release pagination

[futreall]

Fixed unreachable code that could cause infinite loop when searching for releases with specific tag prefixes.

What was wrong:
The code had an impossible condition - it checked if TagPrefix was empty, then if it wasn't empty, and then had a third check that could never run because the first two already covered everything.

This meant that when looking for a release with a specific prefix (like "op-node"), if that release didn't exist, the code would keep searching forever instead of stopping when it ran out of pages.

What changed:
Moved the "no more pages" check to where it actually makes sense - inside the prefix search logic. Now it properly stops when either finding the release or running out of pages to check.

Why it matters:
Prevents the dependency updater from getting stuck in an endless loop when a tagged release doesn't exist in a repository.

[cb-heimdall]

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