[REVERT] Revert changes to env source nested alias test (separated to another PR)

Author: ololoks

tests/test_settings.py

@@ -2738,18 +2738,18 @@ class Settings(BaseSettings):
 
 def test_case_insensitive_nested_optional(env):
     class NestedSettings(BaseModel):
-        FOO: str = Field(..., alias='Foo')
+        FOO: str
         BaR: int
 
     class Settings(BaseSettings):
         model_config = SettingsConfigDict(env_nested_delimiter='__', case_sensitive=False)
 
-        nEstEd: Optional[NestedSettings] = Field(..., alias='NesTed')
+        nested: Optional[NestedSettings]
 
     env.set('nested__FoO', 'string')
     env.set('nested__bar', '123')
     s = Settings()
-    assert s.model_dump() == {'nEstEd': {'BaR': 123, 'FOO': 'string'}}
+    assert s.model_dump() == {'nested': {'BaR': 123, 'FOO': 'string'}}
 
 
 def test_case_insensitive_nested_list(env):