bug: Fix inverted hide_avg_cpu option in config

[ClementTsang]

Description

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Fixes inverted behaviour of the hide_avg_cpu config entry.

Issue

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Closes: #325

Type of change

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• Bug fix (non-breaking change which fixes an issue)

Test methodology

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• Windows
• macOS
• Linux

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Checklist

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• Change has been tested to work, and does not cause new breakage unless intended
• Code has been self-reviewed
• Documentation has been added/updated if needed (README, help menu, etc.)
• Passes CI pipeline (clippy check and cargo test check)
• Areas your change affects have been linted using rustfmt (cargo fmt)
• No merge conflicts arise from the change

Other information

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