Add graphman unassign/reassign commands to graphman graphql api #9003

Job	Run time
Subgraph Runner integration tests	4m 14s
Clippy linting	3m 25s
Run integration tests	3m 56s
Build in release mode	2m 20s
Check rustfmt style	5s
Run unit tests	4m 24s
	18m 24s

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