fix(dependency_updater): prevent infinite pagination loop by checking NextPage before advancing

[Fibonacci747]

The previous pagination logic placed the resp.NextPage == 0 check in an unreachable else if branch competing with TagPrefix conditions. As a result, when TagPrefix != "" and no matching release is found on the last page, the code set options.Page = 0 and could loop indefinitely.

This change:

• Moves the resp.NextPage == 0 termination check to run before assigning options.Page = resp.NextPage.
• Removes the unreachable else if resp.NextPage == 0 branch.

The new flow follows the official go-github pagination example pattern, ensuring the loop exits correctly and preventing infinite iteration.

[cb-heimdall]

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