change to inner product

[MonkeyKing-1]

Babybear now uses gate.inner_product() to save on a few cells for ext multiply (which is called a lot). Seems to give 10% decrease in cells for this test: halo2::tests::stark::test_fibonacci

[github-actions]

group	app.proof_time_ms	app.cycles	app.cells_used	leaf.proof_time_ms	leaf.cycles	leaf.cells_used
verify_fibair	(+133 [+5.9%]) 2,391	513,713	19,375,651	-	-	-
fibonacci_program	(+630 [+11.5%]) 6,116	1,500,137	51,487,838	-	-	-
regex_program	(+1589 [+9.3%]) 18,741	4,190,904	165,010,909	-	-	-
fib_e2e	41,617	12,000,137	410,699,582	54,219	11,453,453	437,454,205
ecrecover_program	(+122 [+4.9%]) 2,618	285,401	15,075,033	-	-	-

Commit: 11f9a1d

Benchmark Workflow