graph: Revert earliest_block off-by-one fix from #6340 #11265

Job	Run time
Build in release mode	1m 46s
Subgraph Runner integration tests	2m 48s
Check rustfmt style	17s
Run unit tests	3m 14s
Clippy linting	1m 43s
Run integration tests	4m 28s
Run unit tests	3m 39s
Build in release mode	1m 46s
Subgraph Runner integration tests	2m 48s
Run integration tests	4m 28s
Clippy linting	1m 43s
Check rustfmt style	17s
	28m 57s

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