[misc] Prepare for 1.12.0 release

[prathapsridharan]

This release of the census package is being done to include an important update for tiledbsoma in 1.9.0 which includes a fix to categorical columns. To ensure that this release goes smoothly, we will:

1. Run an acceptance test off TileDB-SOMA main branch which contains the fixes that will go into 1.9.0. We can think of this as a pre-release acceptance test
2. After (1) passes and the tiledb folks officially release tiledbsoma==1.9.0, we will update the dependencies in this PR to point to tiledbsoma==1.9.0 and do the official release of cellxgene-census==1.12.0

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 81.33%. Comparing base (aa1439f) to head (b1a300b).

Files	Patch %	Lines
...us/src/cellxgene_census/experimental/_embedding.py	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1061 +/- ## ======================================= Coverage 81.33% 81.33% ======================================= Files 73 73 Lines 5566 5566 ======================================= Hits 4527 4527 Misses 1039 1039 ``` | [Flag](https://app.codecov.io/gh/chanzuckerberg/cellxgene-census/pull/1061/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-census/pull/1061/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg) | `81.33% <50.00%> (ø)` | | 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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