Remove lodash isArray + assign

[jimmywarting]

Description

I removed and replaced lodash/isArray with native Array.isArray
Same for assign

Motivation and Context

part of #2187

How Has This Been Tested?

executed test

Types of changes

• No code changes (changes to documentation, CI, metadata, etc)
• Dependency changes (any modification to dependencies in package.json)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Refactor

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[char0n]

For reference here are link that documents distinctions between lodash.assign and Object.assign:

• Note: This method mutates object and is loosely based on Object.assign (from lodash docs)
• https://stackoverflow.com/questions/37123425/object-assign-vs-lodash-assign

[char0n]

LGTM. Thanks again for your work!

[swagger-bot]

🎉 This PR is included in version 3.17.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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