xrootd now needs to be installed separately

### Environment: (where does this bug occur, have you tried other environments)

- Which branch (often `main` for latest released): main
- Environment: Codespaces

### Steps to reproduce: (give a step by step account of how to trigger the bug)

- Open project in codespaces (it opens fine)
- Try running notebooks cells that open remote root file
- This produces an error:

```
---------------------------------------------------------------------------
ModuleNotFoundError Traceback (most recent call last)
File /opt/conda/envs/analysis/lib/python3.12/site-packages/uproot/extras.py:98, in XRootD_client()
97 try:
---> 98 import XRootD
99 import XRootD.client

ModuleNotFoundError: No module named 'XRootD'

The above exception was the direct cause of the following exception:

ModuleNotFoundError Traceback (most recent call last)
/workspaces/python-analysis-bootcamp/Getting Started.ipynb Cell 10 line 1
----> [1](vscode-notebook-cell://codespaces%2Bjubilant-palm-tree-5rjr5g9rv7344x6/workspaces/python-analysis-bootcamp/Getting%20Started.ipynb#X12sdnNjb2RlLXJlbW90ZQ%3D%3D?line=0) events = ur.open(server + dir + file + ':events')

File /opt/conda/envs/analysis/lib/python3.12/site-packages/uproot/reading.py:143, in open(path, object_cache, array_cache, custom_classes, decompression_executor, interpretation_executor, **options)
134 if not uproot._util.isstr(file_path) and not (
135 hasattr(file_path, "read") and hasattr(file_path, "seek")
136 ):
137 raise ValueError(
138 "'path' must be a string, pathlib.Path, an object with 'read' and "
139 "'seek' methods, or a length-1 dict of {file_path: object_path}, "
140 f"not {path!r}"
141 )
--> 143 file = ReadOnlyFile(
...
ModuleNotFoundError: Install XRootD python bindings with:

conda install -c conda-forge xrootd
```