remove evo2 long context train test (#732)

### Description
Marking as xfail unit tests
:sub-packages/bionemo-evo2/tests/bionemo/evo2/run/test_train.py::test_train_single_gpu[7b_arc_longcontext]
due to its issues on certain GPUs

Issue as a follow-up:
#731

### Type of changes
<!-- Mark the relevant option with an [x] -->

- [x]  Bug fix (non-breaking change which fixes an issue)
- [ ]  New feature (non-breaking change which adds functionality)
- [ ]  Refactor
- [ ]  Documentation update
- [ ]  Other (please describe):

### CI Pipeline Configuration
Configure CI behavior by applying the relevant labels:

-
[SKIP_CI](https://github.com/NVIDIA/bionemo-framework/blob/main/docs/docs/user-guide/contributing/contributing.md#skip_ci)
- Skip all continuous integration tests
-
[INCLUDE_NOTEBOOKS_TESTS](https://github.com/NVIDIA/bionemo-framework/blob/main/docs/docs/user-guide/contributing/contributing.md#include_notebooks_tests)
- Execute notebook validation tests in pytest
-
[INCLUDE_SLOW_TESTS](https://github.com/NVIDIA/bionemo-framework/blob/main/docs/docs/user-guide/contributing/contributing.md#include_slow_tests)
- Execute tests labelled as slow in pytest for extensive testing


> [!NOTE]
> By default, the notebooks validation tests are skipped unless
explicitly enabled.

### Usage
<!--- How does a user interact with the changed code -->
```python
TODO: Add code snippet
```

### Pre-submit Checklist
<!--- Ensure all items are completed before submitting -->

 - [ ] I have tested these changes locally
 - [ ] I have updated the documentation accordingly
 - [ ] I have added/updated tests as needed
 - [ ] All existing tests pass successfully

---------

Signed-off-by: Dorota Toczydlowska <[email protected]>

Author: dorotat-nv

sub-packages/bionemo-evo2/tests/bionemo/evo2/run/test_train.py

@@ -130,8 +130,11 @@ def extract_global_steps(log_string):
 
 
 @pytest.mark.slow
+@pytest.mark.parametrize(
+    "model_size",
+    ["1b_nv"],
+)
 @pytest.mark.skip(reason="This test requires a gpu larger than the 24Gb L4s available on GitHub Actions.")
-@pytest.mark.parametrize("model_size", ["7b_nv", "7b_arc_longcontext"])
 def test_train_single_gpu(tmp_path, model_size: str):
     """
     This test runs them single gpu evo2 training command with sample data in a temporary directory.
@@ -170,7 +173,7 @@ def test_train_single_gpu(tmp_path, model_size: str):
 
 @pytest.mark.slow
 @pytest.mark.distributed
-@pytest.mark.parametrize("model_size", ["7b_nv"])
+@pytest.mark.parametrize("model_size", ["1b_nv"])
 @pytest.mark.skip(
     reason="This tests requires to be run on a multi-gpu machine with torchrun --nproc_per_node=N_GPU -m pytest TEST_NAME"
 )