[GPU] Fix dynamic layout calling of get_dims() in prepare_buffer_fusing (#33108)
### Details
- Changed to get single dim from partial_shape when get_dims is not
available for dynamic layout
### Description of the issue
#### Symptom
E2E test for Pytorch_YoloV9_api_2_True will be failed at "get_dims()"
for "__module.model.22/aten::cat/Concat_4" node during
prepare_buffer_fusing pass.
#### Root cause
"__module.model.22/aten::cat/Concat_4" node has 2 dependent nodes as its
inputs. The layout of 1 of the dependent node is dynamic and used to
call "get_dims()", which caused the issue.
#### How to fix it
The concat_axis dim in dims is not dynamic, and can be used to
get_length().
#### The code and line that caused this issue
- get_dims
https://github.com/openvinotoolkit/openvino/blob/4d25dd6aa95acc7f043d06a9ba6ed160530e4025/src/plugins/intel_gpu/src/graph/graph_optimizer/prepare_buffer_fusing.cpp#L323
#### Reproduction step and snapshot
```python -m pytest test_ovc_mo.py --tb=native --env_conf=.automation/env_config.yml --test_conf=test_config_local.yml -m "not launch_only_if_manually_specified " --pregen_irs=python_api_serialized/irs_mapping.csv --tf_models_version=1.15.2 --modules pipelines/production/pytorch/heavy/yolov9.py -k "Pytorch_YoloV9_api_2_True" --dynamism_type=None```
#### Problematic graph
- get_dims with dynamic layout (dep 1)
<img width="1521" height="923" alt="image" src="https://github.com/user-attachments/assets/b59a8fe6-9e1c-4f06-9dcf-eac3a2612a9b" />
#### Checklist
- [ ] Is it a proper fix? (not a workaround)
- [ ] Did you include test case for this fix, if necessary?
- [ ] Did you review existing test that can be extended to cover this scenario? Which test did you review?
### Tickets:
- CVS-101242
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Signed-off-by: yuan.xiong <yuan.xiong@intel.com>
openvino
fbfc5cd2 - [GPU] Fix dynamic layout calling of get_dims() in prepare_buffer_fusing (#33108)
