[Traits] swift package edit and swift package unedit should support trait options

[bripeticca]

Is it reproducible with SwiftPM command-line tools: swift build, swift test, swift package etc?

• Confirmed reproduction steps with SwiftPM CLI. The description text must include reproduction steps with either of command-line SwiftPM commands, swift build, swift test, swift package etc.

Description

The swift package edit and swift package unedit commands don't currently support passing in a trait configuration despite having a path for computing dependency resolution - this will disrupt the dependency graph for packages relying on enabled/disabled trait configurations.

Expected behavior

The edit and unedit commands should support traits (as swift run, swift build, swift package resolve etc. do) in their available options.

Actual behavior

Traits are not supported as a current option.

Steps to reproduce

No concrete steps of reproduction besides taking note of the fact that there is no entry point into swift package edit and swift package unedit for configuring traits - can make note of this in both the source code where the command structs themselves do not have a TraitOptions property, and in CLI when running swift package edit --help/swift package unedit --help.

Swift Package Manager version/commit hash

No response

Swift & OS version (output of swift --version ; uname -a)

No response