Remove support for schemas that are loaded from a URL (breaking)

[ATorrise]

What It Does
Removes support for loading a JSON schema from a remote http(s):// URL via a config file's $schema property.

• validate_config_json (used during profile loading) now raises a ValueError if $schema is an http(s):// URL, telling the user to use a local file path instead.
• ConfigFile.schema_list (used by get_env) now returns an empty list and logs/warns instead of making a network request for a remote $schema URL.

Only local schema files (absolute path, relative path, or file://) are supported now.

How to Test
run the new tests and make sure they pass

Review Checklist
I certify that I have:

• updated the changelog
• manually tested my changes
• added/updated automated unit/integration tests
• created/ran system tests (provide build number if applicable)
• followed the contribution guidelines

Additional Comments
Breaking! Cases where $schema points at a remote url now fail instead of silently succeeding

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.36%. Comparing base (91f8021) to head (c145921).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #412      +/-   ##
==========================================
+ Coverage   83.06%   83.36%   +0.29%     
==========================================
  Files          49       49              
  Lines        2982     2975       -7     
==========================================
+ Hits         2477     2480       +3     
+ Misses        505      495      -10     

Flag	Coverage Δ
unittests	83.36% <100.00%> (+0.29%)	⬆️

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[zFernand0]

LGTM! 😋

I do have one small request about raising the error.
Feel free to get other developer's opinion on this.

[zFernand0]

We seem to be using this same string in multiple paces... wondering if we could move it somewhere else and reuse it.

[zFernand0]

I think we should be raising the error regardless.

Right now, the only place that's calling the schema_list function is inside the get_env function, which is only called when the user specifies that they want to override_with_env.

If we return an empty list here, the developer/user may not realize that their environment variables were not loaded because the schema comes from a URL. This leads to unexpected behavior.