[Bug]: Specification - TaskList defined only for gRPC and JSON+HTTP in the spect but not in the proto

### What happened?

The spec defines (§7.3) method TaskList for gRPC and JSON-HTTP, but proto miss the definition.
COnsidering the JSONRPC doesn't have the method (neither in spec nor in json) it seems reasonable to ridd it off from the spec 

### Relevant log output

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