[Cherry-pick] DYN-7394 Retire two feature flags used for DynamoHome and TSpline node

[QilongTang]

Purpose

Cherry-pick #15596

Declarations

Check these if you believe they are true

• The codebase is in a better state after this PR
• Is documented according to the standards
• The level of testing this PR includes is appropriate
• User facing strings, if any, are extracted into *.resx files
• All tests pass using the self-service CI.
• Snapshot of UI changes, if any.
• Changes to the API follow Semantic Versioning and are documented in the API Changes document.
• This PR modifies some build requirements and the readme is updated
• This PR contains no files larger than 50 MB

Release Notes

Retire two feature flags used for DynamoHome and TSpline node

Reviewers

@DynamoDS/dynamo

FYIs

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[github-actions]

UI Smoke Tests

Test: success. 11 passed, 0 failed.
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