Agent error tracing does not work and throws errors to stderr itself

**Describe the bug**
```
[Elastic APM PHP Tracer] 2024-09-03 19:13:10.806440+00:00 [PID: 1647] [TID: 1647] [ERROR] [Util] [util_for_PHP.cpp:217] [callPhpFunction] call_user_function failed. Return value: -1. PHP function name: `\Elastic\Apm\Impl\AutoInstrument\PhpPartFacade::internalFuncCallPostHook'. argsCount: 2.
[Elastic APM PHP Tracer] 2024-09-03 19:13:10.806570+00:00 [PID: 1647] [TID: 1647] [ERROR] [Util] [util_for_PHP.cpp:230] [callPhpFunction] Exiting...; resultCode: resultFailure (6);
[Elastic APM PHP Tracer] 2024-09-03 19:13:10.806603+00:00 [PID: 1647] [TID: 1647] [ERROR] [C-to-PHP] [tracer_PHP_part.cpp:90] [switchTracerPhpPartStateToFailed] Switching tracer PHP part state to failed; reason: Failed to call tracer PHP part, current state: tracerPhpPartState_after_bootstrap, called from tracerPhpPartInternalFuncCallPostHook
[Elastic APM PHP Tracer] 2024-09-03 19:13:10.806638+00:00 [PID: 1647] [TID: 1647] [ERROR] [C-to-PHP] [tracer_PHP_part.cpp:295] [tracerPhpPartInternalFuncCallPostHook] Exiting...; resultCode: resultFailure (6); dbgInterceptRegistrationId: 8; interceptedCallRetValOrThrown type: 2.
```

**To Reproduce**
Steps to reproduce the behavior:
1. Use this config
```
; This file contains the various settings for the Elastic APM PHP agent. For
; further details refers to the following URL:
; https://www.elastic.co/guide/en/apm/agent/php/current/configuration-reference.html
;

[elastic]
elastic_apm.enabled = ${ELASTIC_APM_AGENT_ENABLED}
elastic_apm.abort_on_memory_leak = ${ELASTIC_APM_AGENT_ABORT_ON_MEMORY_LEAK}
elastic_apm.server_url = ${ELASTIC_APM_AGENT_SERVER_URL}
elastic_apm.server_timeout = ${ELASTIC_APM_AGENT_SERVER_TIMEOUT}
elastic_apm.verify_server_cert = ${ELASTIC_APM_AGENT_VERIFY_SERVER_CERTIFICATE}
;elastic_apm.api_key = "REPLACE_WITH_API_KEY"
;elastic_apm.secret_token = "REPLACE_WITH_SECRET_TOKEN"
elastic_apm.disable_instrumentations = ${ELASTIC_APM_AGENT_DISABLE_INSTRUMENTATIONS}
elastic_apm.transaction_max_spans = ${ELASTIC_APM_AGENT_TRANSACTION_MAX_SPANS}
elastic_apm.transaction_sample_rate = 1.0
elastic_apm.environment = "${ELASTIC_APM_AGENT_ENVIRONMENT}"
elastic_apm.hostname = ${ELASTIC_APM_AGENT_HOSTNAME}
elastic_apm.service_name = "${ELASTIC_APM_AGENT_SERVICE_NAME}"
elastic_apm.service_node_name = "${ELASTIC_APM_AGENT_SERVICE_NODE_NAME}"
elastic_apm.service_version = "${ELASTIC_APM_AGENT_SERVICE_VERSION}"
elastic_apm.global_labels = "${ELASTIC_APM_AGENT_GLOBAL_LABELS}"
elastic_apm.log_level = "${ELASTIC_APM_AGENT_LOG_LEVEL}"
elastic_apm.log_level_stderr = "${ELASTIC_APM_AGENT_LOG_LEVEL_STDERR}"
elastic_apm.capture_errors = "${ELASTIC_APM_AGENT_CAPTURE_ERRORS}"
elastic_apm.stack_trace_limit = "${ELASTIC_APM_AGENT_STACK_TRACE_LIMIT}"
```
the env values are as follows:
```
ELASTIC_APM_AGENT_ABORT_ON_MEMORY_LEAK=false
ELASTIC_APM_AGENT_ENABLED=true
ELASTIC_APM_AGENT_SERVICE_VERSION=N/A
ELASTIC_APM_AGENT_DISABLE_INSTRUMENTATIONS=
ELASTIC_APM_AGENT_LOG_LEVEL=info
ELASTIC_APM_AGENT_SERVICE_NAME=php8-fpm_1
ELASTIC_APM_AGENT_LOG_LEVEL_STDERR=info
ELASTIC_APM_AGENT_SERVER_TIMEOUT=5s
ELASTIC_APM_AGENT_HOSTNAME=adex-php8-fpm_1
ELASTIC_APM_AGENT_VERSION=1.12.0
ELASTIC_APM_AGENT_GLOBAL_LABELS=
ELASTIC_APM_AGENT_ENVIRONMENT=local
ELASTIC_APM_AGENT_TRANSACTION_MAX_SPANS=500
ELASTIC_APM_AGENT_CAPTURE_ERRORS=on
ELASTIC_APM_AGENT_SERVER_URL=http://elastic-apm-server:8200
ELASTIC_APM_AGENT_VERIFY_SERVER_CERTIFICATE=false
ELASTIC_APM_AGENT_STACK_TRACE_LIMIT=-1
ELASTIC_APM_AGENT_SERVICE_NODE_NAME=N/A
```
2. Run a console script that throws an exception