refactor: use maps.Copy for cleaner map handling

[pingshuijie]

There is a new function added in the go1.21 standard library, which can make the code more concise and easy to read.

[graphite-app]

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[macroscopeapp]

Replace manual map copying with maps.Copy in XmtpdContainerBuilder.WithEnvVars method for cleaner map handling

The WithEnvVars method in the XmtpdContainerBuilder struct now uses the standard library maps.Copy function instead of manually iterating through map entries. The change adds an import for the maps package and replaces the manual loop-based copying with maps.Copy(b.envVars, envVars) in pkg/integration/docker_utils_test.go.

📍Where to Start

Start with the WithEnvVars method in the XmtpdContainerBuilder struct in pkg/integration/docker_utils_test.go.

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Macroscope summarized d428374.