Switch to depending on datasette-llm not datasette-llm-accountant

[simonw]

Plugin currently depends on datasette-llm-accountant:

datasette-extract/pyproject.toml

Line 20 in bf7cb3b

"datasette-llm-accountant>=0.1a1",

But that's no longer necessary - we redesigned datasette-llm and datasette-llm-accountant such that accountant is an optional plugin which works with any plugin that uses datasette-llm directly.

[simonw]

Related (and just shipped in datasette-llm>=0.1a3):

• Support configuring the models that are default/available for specific purposes datasette-llm#3