Update sparse_finch notebook and upgrade finch-tensor

[mtsokol]

This PR upgrades finch-tensor to 0.2.1 and updates sparse_finch.ipynb to also include "Finch - Galley" configuration and Counting triangles example.

[hameerabbasi]

LGTM, just the nit below.

[mtsokol]

We still need to wait for finch-tensor/finch-tensor-python#79

[codspeed-hq]

CodSpeed Performance Report

Merging #820 will degrade performances by 13.78%

_{Comparing notebook-update (1c4d5c6) with main (128a567)}

Summary

❌ 2 regressions
✅ 338 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	notebook-update	Change
❌	test_index_fancy[side=100-rank=1-format='coo']	1.2 ms	1.4 ms	-13.78%
❌	test_index_slice[side=100-rank=2-format='gcxs']	2.2 ms	2.5 ms	-11.86%

[mtsokol]

@hameerabbasi Let's upgrade finch-tensor here also and skip #823. Here's no need to have it in a separate PR.

[hameerabbasi]

Thanks for the update, @mtsokol!

[mtsokol]

@hameerabbasi I promise this is the last one 😅 Can you re-approve? Now it's all green!

[mtsokol]

Merged! I think we can cut first beta release!