chore(build): propagate --inplace (#14741)

## Description

`setup.py build_ext --inplace` places built `.so` files under `build/`
directory instead of placing them next to the sources as intended. Check
`--inplace` is set and use it.

## Testing

<!-- Describe your testing strategy or note what tests are included -->

## Risks

<!-- Note any risks associated with this change, or "None" if no risks
-->

## Additional Notes

<!-- Any other information that would be helpful for reviewers -->

Author: taegyunkim

setup.py

@@ -302,7 +302,7 @@ def run(self):
                 has_profiling_feature = True
                 break
 
-        if IS_EDITABLE:
+        if IS_EDITABLE or getattr(self, "inplace", False):
             self.inplace = True
 
         super().run()
@@ -528,6 +528,8 @@ def build_rust(self):
         build_rust_cmd = CustomBuildRust(self.distribution)
         build_rust_cmd.initialize_options()
         build_rust_cmd.finalize_options()
+        # Propagate the inplace flag to the rust build command
+        build_rust_cmd.inplace = getattr(self, "inplace", False)
         build_rust_cmd.run()
 
         self.suffix = sysconfig.get_config_var("EXT_SUFFIX")