feat: add term label to OntologyNode

[nayib-jose-gloria]

Reason for Change

• Cell Guide uses term label in their subtree implementation, this simplifies their integration with COG

Changes

• add "name" property to OntologyNode
• update dict representation of OntologyNode to accommodate this additional metadata on each node

Testing steps

• Either list QA steps or reasoning you feel QA is unnecessary
• Describe how you made sure to know that your changes worked. Should allow someone else to go verify your code without in depth knowledge.

Notes for Reviewer

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 85.05%. Comparing base (186e762) to head (dfccf48).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #182 +/- ## ========================================== + Coverage 84.98% 85.05% +0.07% ========================================== Files 19 19 Lines 1059 1064 +5 Branches 199 200 +1 ========================================== + Hits 900 905 +5 Misses 149 149 Partials 10 10 ``` | [Flag](https://app.codecov.io/gh/chanzuckerberg/cellxgene-ontology-guide/pull/182/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/chanzuckerberg/cellxgene-ontology-guide/pull/182/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg) | `85.05% <100.00%> (+0.07%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg#carryforward-flags-in-the-pull-request-comment) to find out more.

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