[ML][Pipelines] fix: add environment_variable to CommandComponent schema

[elliotzh]

Description

• add environment_variable to some internal components
• make internal CommandComponent/ParallelComponent inheriting parameterized schema to reduce maintenance cost

All SDK Contribution checklist:

• [x] The pull request does not introduce [breaking changes]
• [x] CHANGELOG is updated for new features, bug fixes or other significant changes.
• [x] I have read the contribution guidelines.

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Testing Guidelines

• [ ] Pull request includes test coverage for the included changes.