core:status command returns inconsistent output

[fchavant]

Expected behavior

lisk core:status always returns the same kind of output (e.g. always JSON)

Actual behavior

lisk core:status may return JSON or a plain text error message (if there are no installed instances)

Steps to reproduce

lisk core:status  # not JSON
lisk core:install lisk-mainnet
lisk core:status  # JSON

Which version(s) does this affect? (Environment, OS, etc...)

2.2.2