Context

Fixes #1276 (closed) by adding a check for delegate registration in each context/delegate/tz*/* RPC.

Manually testing the MR

Run the commands in the description of #1276 (closed) and check that the error messages make sense.

Document the interface of any function added or modified (see the coding guidelines)
Document any change to the user interface, including configuration parameters (see node configuration)
Provide automatic testing (see the testing guide).
For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
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Edited Aug 27, 2021 by Raphaël Cauderlier