Disable checksum search from listing admin list

Disable searching on file checksums from the package listing
admin list view as the queries take too long to run against the
production dataset.

django/thunderstore/community/admin/package_listing.py

@@ -64,7 +64,6 @@ class PackageListingAdmin(admin.ModelAdmin):
         "package__namespace__name",
         "package__owner__name",
         "package__name",
-        "package__versions__file_tree__entries__blob__checksum_sha256",
     )
     list_select_related = (
         "package",