Move output path to be inside the wheel build command execution loop

This was causing an issue when building multiple wheels in editable mode.

i.e instead of wheels being stored as:
```
# jax-cuda12-pjrt   0.4.36.dev20241125           ./dist/jax-cuda-pjrt
# jax-cuda12-plugin 0.4.36.dev20241125           ./dist/jax-cuda-plugin
# jaxlib            0.4.36.dev20241125           ./dist/jaxlib
```

they were being stored as:
```
# jaxlib            0.4.36.dev20241125           ./dist/jaxlib
# jax-cuda12-pjrt   0.4.36.dev20241125           ./dist/jaxlib/jax-cuda-pjrt
# jax-cuda12-plugin 0.4.36.dev20241125           ./dist/jaxlib/jax-cuda-plugin
```

PiperOrigin-RevId: 708468522

build/build.py

@@ -580,11 +580,11 @@ async def main():
   if args.configure_only:
     logging.info("--configure_only is set so not running any Bazel commands.")
   else:
-    output_path = args.output_path
-    logger.debug("Artifacts output directory: %s", output_path)
-
     # Wheel build command execution
     for wheel in args.wheels.split(","):
+      output_path = args.output_path
+      logger.debug("Artifacts output directory: %s", output_path)
+
       # Allow CUDA/ROCm wheels without the "jax-" prefix.
       if ("plugin" in wheel or "pjrt" in wheel) and "jax" not in wheel:
         wheel = "jax-" + wheel