fix bootstrap error

[benjiewheeler]

Description

One of the protocol feature activations fails with the following error

Error 3100010: JSON parse exception
Error Details:
Fail to parse JSON from string: ["8ba52fe7a3956c5cd3a656a3174b931d3bb2abb45578befc59f283ecd816a405"
unexpected end of file
Attempting to parse array ["8ba52fe7a3956c5cd3a656a3174b931d3bb2abb45578befc59f283ecd816a405"]
{"str":"[\"8ba52fe7a3956c5cd3a656a3174b931d3bb2abb45578befc59f283ecd816a405\""}
Stack Trace:
main.cpp:519 json_from_file_or_string
json_relaxed.hpp:744 variant_from_stream
json_relaxed.hpp:651 arrayFromStream
json.cpp:459 from_string

Expected Behavior:

Should activate the protocol features without errors.

Steps to reproduce

# Start a node
dune --start <node_name>
# Do a system bootstrap
dune --bootstrap-system