Serialize instance properties

[doctrino]

Description

Please describe the change you have made.

Checklist:

• [ ] Tests added/updated.
• [ ] Documentation updated. Documentation is generated from docstrings - these must be updated according to your change. If a new method has been added it should be referenced in cognite.rst in order to generate docs based on its docstring.
• [ ] Changelog updated in CHANGELOG.md.
• [ ] Version bumped. If triggering a new release is desired, bump the version number in _version.py and pyproject.toml per semantic versioning.

[codecov[bot]]

Codecov Report

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

Project coverage is 92.85%. Comparing base (9df2dd0) to head (903289c).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1819 +/- ## ========================================== + Coverage 92.78% 92.85% +0.06% ========================================== Files 121 121 Lines 17839 17850 +11 ========================================== + Hits 16552 16574 +22 + Misses 1287 1276 -11 ``` | [Files](https://app.codecov.io/gh/cognitedata/cognite-sdk-python/pull/1819?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cognitedata) | Coverage Δ | | |---|---|---| | [cognite/client/\_version.py](https://app.codecov.io/gh/cognitedata/cognite-sdk-python/pull/1819?src=pr&el=tree&filepath=cognite%2Fclient%2F_version.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cognitedata#diff-Y29nbml0ZS9jbGllbnQvX3ZlcnNpb24ucHk=) | `100.00% <100.00%> (ø)` | | | [...ite/client/data\_classes/data\_modeling/instances.py](https://app.codecov.io/gh/cognitedata/cognite-sdk-python/pull/1819?src=pr&el=tree&filepath=cognite%2Fclient%2Fdata_classes%2Fdata_modeling%2Finstances.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cognitedata#diff-Y29nbml0ZS9jbGllbnQvZGF0YV9jbGFzc2VzL2RhdGFfbW9kZWxpbmcvaW5zdGFuY2VzLnB5) | `92.71% <100.00%> (+0.19%)` | :arrow_up: | ... and [5 files with indirect coverage changes](https://app.codecov.io/gh/cognitedata/cognite-sdk-python/pull/1819/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cognitedata)