fix: 🐞 add missing exports to __all__ in supervision module

[onuralpszr]

Fix: #1681

[LinasKo]

Non-empty __init__ files in repo:

./supervision/metrics/__init__.py
./supervision/__init__.py
./supervision/validators/__init__.py
./supervision/assets/__init__.py

1. I believe we should add this to metrics/__init__.py and assets/__init__.py as well.
2. Instead, do you think this would be a better approach?

import inspect

...

# Explicitly declares public variables; required for pyright. See #1681
__all__ = [
    name
    for name in globals()
    if not name.startswith("_") and not inspect.ismodule(globals()[name])
]

I teste the set of variables I get with this:

print(__all__)
print(__all__2)
print(set(__all__) == set(__all__2))

3. In case you dug this far: Shouldn't the definition of exported variables happen automatically for non-protected methods (without leading _)? Edit: reportPrivateImportUsage error on public-looking symbol defined with relative import microsoft/pyright#2639

Thanks for triaging this issue at such a late hour!

[onuralpszr]

1- For adding others I agreed

2- I like your for loop but the reason I prefer list is because "no import and logicless" sometimes using for loop + import more costly compare to simple list beside adding them not gonna be big of a deal anyway