Add graphman unassign/reassign commands to graphman graphql api #9007

Job	Run time
Subgraph Runner integration tests	7m 8s
Build in release mode	2m 11s
Run integration tests	5m 50s
Clippy linting	1m 14s
Check rustfmt style	7s
Run unit tests	9m 39s
	26m 9s

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