Fix linter warnings — radicle-explorer

Fixes svelte/no-reactive-reassign errors when running scripts/check.

It slipped through code review, regression from: https://app.radicle.xyz/nodes/seed.radicle.garden/rad:z4V1sjrXqjvFdnCUbxPFqd5p4DtH5/patches/d77e0646b32cac18187a72bd5f36b501a08040ba https://github.com/radicle-dev/radicle-explorer/actions/runs/17741958964/job/50417893170

👉 Workflow runs 👉 Branch on GitHub

   let listState: "pinned" | "all" = "pinned";
   $: page = 0;
   let page = 0;
   $: perPage = listState === "pinned" ? stats.repos.total : 24;
   $: totalPages = Math.ceil(stats.repos.total / perPage);