[BUILD] Incorrect test on ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW #2545
Description
In the OTLP GRPC code, usage of the ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW flag is incorrect.
/data/malff/CODE/MY_GITHUB/opentelemetry-cpp/exporters/otlp
[malff@malff-desktop otlp]$ grep -R ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW *
include/opentelemetry/exporters/otlp/otlp_grpc_client_options.h:#ifdef ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW
src/otlp_grpc_client.cc:#if ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW
src/otlp_grpc_metric_exporter_options.cc:#ifdef ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW
src/otlp_grpc_exporter_options.cc:#ifdef ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW
src/otlp_grpc_log_record_exporter_options.cc:#ifdef ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW
File src/otlp_grpc_client.cc should use ifdef, not if.