Cannot import SQLite utilities without icetray.
**Describe the bug**
I would like to import a few utility functions from `graphnet.data.sqlite.sqlite_utilities`, but trying to do so results in an error due to icetray not being installed.

**To Reproduce**
Steps to reproduce the behavior:
1. Activate standard graphnet environment in a clean shell
3. Run `$ python -c "from graphnet.data.sqlite.sqlite_utilities import create_table"`
4. See error

**Expected behavior**
I would expect that such generic utility functions should be importable regardless of whether icetray is installed.

**Full traceback**
Please include the full error message to allow for debugging
```
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/lustre/hpc/icecube/asogaard/work/development/graphnet/src/graphnet/data/sqlite/__init__.py", line 5, in <module>
    from .sqlite_dataconverter import SQLiteDataConverter
  File "/lustre/hpc/icecube/asogaard/work/development/graphnet/src/graphnet/data/sqlite/sqlite_dataconverter.py", line 12, in <module>
    from graphnet.data.dataconverter import DataConverter  # type: ignore[attr-defined]
  File "/lustre/hpc/icecube/asogaard/work/development/graphnet/src/graphnet/data/dataconverter.py", line 31, in <module>
    from graphnet.data.extractors import (
  File "/lustre/hpc/icecube/asogaard/work/development/graphnet/src/graphnet/data/extractors/__init__.py", line 3, in <module>
    from .i3extractor import I3Extractor, I3ExtractorCollection
  File "/lustre/hpc/icecube/asogaard/work/development/graphnet/src/graphnet/data/extractors/i3extractor.py", line 10, in <module>
    from icecube import icetray, dataio  # pyright: reportMissingImports=false
ImportError: cannot import name 'icetray' from 'icecube' (unknown location)
```
diff --git a/src/graphnet/utilities/imports.py b/src/graphnet/utilities/imports.py
index e83050db..b0b69250 100644
--- a/src/graphnet/utilities/imports.py
+++ b/src/graphnet/utilities/imports.py
@@ -10,6 +10,7 @@ def has_icecube_package() -> bool:
     """Check whether the `icecube` package is available."""
     try:
         import icecube  # pyright: reportMissingImports=false
+        from icecube import icetray, dataio
 
         return True
     except ImportError:
['src/graphnet/utilities/imports.py']