test: Add test to confirm programmatic config wins over env in BatchConfig#2781

cijothomas merged 4 commits intoopen-telemetry:mainopen-telemetry/opentelemetry-rust:mainfrom

cijothomas:cijothomas/batch-log-env-var-tescijothomas/opentelemetry-rust:cijothomas/batch-log-env-var-tesCopy head branch name to clipboard