MediaAsset instances with attributes violate equality/hash contract with strings

[miladkhoshdel]

After the fix for #37088, MediaAsset.__eq__() still considers an asset equal to a string containing the same path, while MediaAsset.__hash__() includes the asset's attributes.

This violates Python's requirement that equal objects have equal hashes.

Reproduction on Django 6.2.dev20260831204047:

from django.forms import Script

asset = Script("/static/app.js", defer=True)
path = "/static/app.js"

print(asset == path)
print(hash(asset) == hash(path))
print(path in {asset})

Output:

True
False
False

Although asset == path, a set cannot find path because the two objects are placed in different hash buckets. Dictionary lookups can be affected in the same way. Stylesheet instances with attributes have the same issue.

Expected behavior: Whenever asset == path, hash(asset) == hash(path).

This appears to be a regression introduced by bc9bed573ce39c3b739a4a3b7848816d464b6bdc for #37088 in Django 6.1.

A possible fix is to hash only self._path. Assets with the same path but different attributes may then share a hash while remaining unequal, which is valid Python behavior.