muster release v5.43.0

muster auth login signs in again when the server rejects a stored token that has not expired. A token file whose access token was unexpired by its stored expiry but rejected by the server (the server dropped the session) made the login print Establishing SSO connections... and exit 0 without a browser, a sign-in URL or a token, --force included, and muster auth status stayed Not authenticated until the stored expiry passed. The login now checks the session with the server after reusing the stored one and runs the browser (or --no-browser) flow when the server still answers 401; --force always runs the flow. The command exits 0 only once the server accepts the session, and with exit code 3 when a completed flow leaves none; --server and --all sign in to the aggregator the same way. (#1484)