[generative_ai]: Translation "with LLM" samples are not working anymore.

## In which file did you encounter the issue?

**N/A** — The samples in issue are written as **Markdown**. I worked on replacing them with actual Python samples.

## Did you change the file? If so, how?

No.

## Describe the issue

Both "Translation LLM" samples appear not working anymore ([sample 1](https://cloud.google.com/vertex-ai/generative-ai/docs/translate/translate-text#zero_shot_translation-python), [sample 2](https://cloud.google.com/vertex-ai/generative-ai/docs/translate/translate-text#few_shot_translate-python)).
The SDK fails to create the endpoint using the `cloud-translate-text` LLM provided in the documentation:

```python
from google.cloud import aiplatform

endpoint = aiplatform.Endpoint('projects/PROJECT_ID/locations/LOCATION/publishers/google/models/cloud-translate-text')
...
```

Error:

```
Traceback (most recent call last):
File "/...path/samples/pages/translation/translate_llm.py", line 26, in
translate()
File "/..path/samples/pages/translation/translate_llm.py", line 12, in translate
endpoint = aiplatform.Endpoint(endpoint)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/..path/.venv/lib/python3.12/site-packages/google/cloud/aiplatform/models.py", line 664, in __init__
endpoint_name = utils.full_resource_name(
^^^^^^^^^^^^^^^^^^^^^^^^^
File "/..path/.venv/lib/python3.12/site-packages/google/cloud/aiplatform/utils/__init__.py", line 221, in full_resource_name
resource_id_validator(resource_name)
File "/..path/.venv/lib/python3.12/site-packages/google/cloud/aiplatform/utils/__init__.py", line 157, in validate_id
raise ValueError(f"Resource {resource_id} is not a valid resource id.")
ValueError: Resource projects/[my-actual-project-id]/locations/us-central1/publishers/google/models/cloud-translate-text is not a valid resource id.
```

## Environment

`google-cloud-aiplatform==1.71.1`

Full:

```log
% python -V
Python 3.12.6

% pip list | grep google
google-api-core 2.19.1
google-auth 2.34.0
google-cloud-aiplatform 1.71.1
google-cloud-bigquery 3.25.0
google-cloud-core 2.4.1
google-cloud-resource-manager 1.12.5
google-cloud-storage 2.18.2
google-crc32c 1.5.0
google-resumable-media 2.7.2
googleapis-common-protos 1.64.0
grpc-google-iam-v1 0.13.1
```