fix: convert strict JSON errors to warning

[scarf005]

Purpose of change (The Why)

Json error: data/json/items/generic/bathroom_house.json:27:14: cannot assign explicit value the same as default or inherited value

    "price_postapoc": "150 cent",
    "//": "the end of the world doesn't mean everyone is okay with having ZZ Top beards.  disposable razors are a hot commodity.",
    "weight":
             ^
              "100 g",
    "material": [ "plastic", "steel" ],
    "cutting": 2,

Hints like this should be an warning, not errors that break builds that has been running for 20 minutes, which is highly annoying.

Describe the solution (The How)

adds new macro, debugmsg_of which accepts debug level as first parameter.

Describe alternatives you've considered

Testing

21:18:32.078 WARNING DEBUGMSG : /var/home/scarf/repo/cata/Cataclysm/src/assign.cpp:11 [void report_strict_violation(const JsonObject &, const std::string &, const std::string &)] (json-error)
Json error: data/json/items/generic/bathroom_house.json:27:14: cannot assign explicit value the same as default or inherited value

    "price_postapoc": "150 cent",
    "//": "the end of the world doesn't mean everyone is okay with having ZZ Top beards.  disposable razors are a hot commodity.",
    "weight":
             ^
              "100 g",
    "material": [ "plastic", "steel" ],
    "cutting": 2,


Starting the actual test at Thu Jan 30 21:18:40 2025
[sol2] An exception occurred: Exception thrown on Cpp side!
21:19:56.941 INFO : Language set to 'en_US'
21:19:56.941 INFO : C locale set to 'en_US.UTF-8'
21:19:56.941 INFO : C++ locale set to 'en_US.UTF-8'
21:19:57.148 INFO : Language set to 'fr_FR'
21:19:57.151 INFO : C locale set to 'fr_FR.UTF-8'
21:19:57.151 INFO : C++ locale set to 'fr_FR.UTF-8'
21:19:57.389 INFO : Language set to 'ru_RU'
21:19:57.392 INFO : C locale set to 'ru_RU.UTF-8'
21:19:57.393 INFO : C++ locale set to 'ru_RU.UTF-8'
21:19:57.554 INFO : Language set to 'en_US'
21:19:57.554 INFO : C locale set to 'en_US.UTF-8'
21:19:57.554 INFO : C++ locale set to 'en_US.UTF-8'
===============================================================================
All tests passed (7243965 assertions in 545 test cases)

21:21:14.289 INFO : Setting active world to NULL
Ended test at Thu Jan 30 21:21:14 2025
The test took 153.842 seconds

• caused duplicate value on purpose
• tests passes

Additional context

#6014 bring me here

Checklist

Mandatory

• I wrote the PR title in conventional commit format.
• I ran the code formatter.
• I linked any relevant issues using github keyword syntax like closes #1234 in Summary of the PR so it can be closed automatically.
• I've committed my changes to new branch that isn't main so it won't cause conflict when updating main branch later.