[python] Fix unbound-local error

[johnkerl]

Issue and/or context: Fixes #2499

Changes:

Notes for Reviewer: The customer callpath wasn't provided in its entirety but it's clear where the bug is

[aaronwolen]

[sc-46790]

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 90.25%. Comparing base (676c834) to head (eed5616).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2516   +/-   ##
=======================================
  Coverage   90.25%   90.25%           
=======================================
  Files          37       37           
  Lines        3950     3950           
=======================================
  Hits         3565     3565           
  Misses        385      385           

Flag	Coverage Δ
python	90.25% <0.00%> (ø)

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Components	Coverage Δ
python_api	90.25% <0.00%> (ø)
libtiledbsoma	∅ <ø> (∅)

[ryan-williams]

lgtm, though same problem appears to exist at L1306:

TileDB-SOMA/apis/python/src/tiledbsoma/io/ingest.py

Lines 1305 to 1310 in 33022c6

	except (AlreadyExistsError, NotCreateableError):
	if ingestion_params.error_if_already_exists:
	raise SOMAError(f"{soma_ndarray.uri} already exists")
	soma_ndarray = cls.open(
	uri, "w", platform_config=platform_config, context=context
	)

(here on #2434)

[johnkerl]

lgtm, though same problem appears to exist at L1306:

Thanks @ryan-williams ! #2522