fix(routers.pkgbase): fix next argument for merge redirection

This was redirecting us to the package which we merged, leading
us into a 404. This fixes that issue by instead redirecting us
into the target we merge into.

Closes #231

Signed-off-by: Kevin Morris <kevr@0cost.org>

aurweb/routers/pkgbase.py

@@ -785,9 +785,6 @@ async def pkgbase_merge_get(request: Request, name: str,
                             next: str = Query(default=str())):
     pkgbase = get_pkg_or_base(name, PackageBase)
 
-    if not next:
-        next = f"/pkgbase/{pkgbase.Name}"
-
     context = templates.make_context(request, "Package Merging")
     context.update({
         "pkgbase": pkgbase,