chore: ignore pre-release tags for version docs build (#11900)

# Which Problems Are Solved

For switching v4.x releases to a corresponding maintenance branch, we
had to trick semantic release and create a `5.0.0-base` tag on main.
This now breaks the docs build, which tries to fetch all tags and build
a corresponding version.

# How the Problems Are Solved

- Ignore pre-released tags/releases for the moment.

# Additional Changes

None

# Additional Context

- requires backport to v4.x

apps/docs/scripts/fetch-remote-content.mjs

@@ -108,7 +108,10 @@ export function filterVersions(tags) {
       const valid = semver.valid(v);
       if (!valid) return false;
       // Strict cutoff: Do not fetch or build anything older (including that version)
-      return semver.gt(v, CUTOFF);
+      const isAboveCutoff = semver.gt(v, CUTOFF);
+      if (!isAboveCutoff) return false;
+
+      return semver.prerelease(v) === null;
     })
     .sort((a, b) => semver.rcompare(a, b));