dev-cmd/extract: remove old DependencyCollector::Compat handling

[Bo98]

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This was needed as a temporary measure due to some dependency-related deprecation. DependencyCollector::Compat no longer exists so this monkey patch is never invoked and can be removed.

[BrewTestBot]

Review period will end on 2021-09-13 at 23:20:50 UTC.

[BrewTestBot]

Review period ended.