fix: remove unused CC0-1.0 license from REUSE configuration

Remove CC0-1.0 annotation for non-existent .github/CODEOWNERS file from
REUSE.toml. This file is not part of the project and was causing REUSE
compliance checks to fail.

Remove unused CC0-1.0.txt license file from LICENSES directory as it is
not referenced by any project files.

Project now only uses:
- AGPL-3.0-or-later: Main project code
- MIT: Nextcloud template workflows

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

LICENSES/CC0-1.0.txt

@@ -8,12 +8,6 @@ SPDX-PackageDownloadLocation = "https://github.com/LibreSign/wordpress_login_bac
 default-license = "AGPL-3.0-or-later"
 default-copyright = "2026 LibreCode coop and contributors"
 
-[[annotations]]
-path = ".github/CODEOWNERS"
-precedence = "aggregate"
-SPDX-FileCopyrightText = "none"
-SPDX-License-Identifier = "CC0-1.0"
-
 [[annotations]]
 path = [
     "appinfo/info.xml",