help request: Secrets gcp integration error

### Description

I'm trying to configure GCP secrets integration, but I'm receiving this error:

```
apisix-7948456797-vdrtj apisix 2025/11/28 04:07:59 [error] 49#49: *17968 lua entry thread aborted: runtime error: unknown reason
apisix-7948456797-vdrtj apisix stack traceback:
apisix-7948456797-vdrtj apisix coroutine 0:
apisix-7948456797-vdrtj apisix [C]: in function 'error'
apisix-7948456797-vdrtj apisix /usr/local/apisix//deps/share/lua/5.1/resty/jwt.lua:572: in function 'sign'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/utils/google-cloud-oauth.lua:92: in function 'generate_jwt_token'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/utils/google-cloud-oauth.lua:54: in function 'refresh_access_token'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/utils/google-cloud-oauth.lua:41: in function 'generate_access_token'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/secret/gcp.lua:109: in function 'get_secret'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/secret/gcp.lua:161: in function 'make_request_to_gcp'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/secret/gcp.lua:184: in function 'get'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/secret.lua:156: in function 'fetch_by_uri'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/secret.lua:178: in function 'fetch'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/secret.lua:214: in function 'fetch_secrets'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/consumer.lua:241: in function 'create_obj_fun'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/core/lrucache.lua:111: in function 'consumer_lrucache'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/consumer.lua:250: in function 'create_obj_fun'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/core/lrucache.lua:111: in function 'lrucache'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/consumer.lua:262: in function 'consumers_kv'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/consumer.lua:276: in function 'find_consumer'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/plugins/key-auth.lua:83: in function 'find_consumer'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/plugins/key-auth.lua:104: in function 'phase_func'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/plugin.lua:1194: in function 'run_plugin'
apisix-7948456797-vdrtj apisix /usr/local/apisix/apisix/init.lua:788: in function 'http_access_phase'
```

### Environment

- APISIX version (run `apisix version`): 3.14
- Operating system (run `uname -a`): oficial image 3.14
- OpenResty / Nginx version (run `openresty -V` or `nginx -V`):
- etcd version, if relevant (run `curl http://127.0.0.1:9090/v1/server_info`):
- APISIX Dashboard version, if relevant:
- Plugin runner version, for issues related to plugin runners:
- LuaRocks version, for installation issues (run `luarocks --version`):