Specifying artifact regististry images with tags fails

Creating a PipelineJob based on a artifact registry URI using a **tag** instead of a **version** raises an internal server error.
This is pretty annoying.

### to be clear:

- Using an artifact with sha256 version number works:
https://europe-west1-kfp.pkg.dev/my-project/my-project-kfp-template-repository/my-pipeline/sha256:3456789874334a...

- Using a tag gives a 500 internal server error:
https://europe-west1-kfp.pkg.dev/my-project/my-project-kfp-template-repository/my-pipeline/my-tag

- Using a tag that doesn't exist gives a 404 error when creating the PipelineJob
https://europe-west1-kfp.pkg.dev/my-project/my-project-kfp-template-repository/my-pipeline/my-non-existent-tag

All of this combined makes it seem like there's a bug for executing tagged artifacts.

#### Environment details

- OS type and version: Ubuntu 22.04.2 LTS
- Python version: Python 3.9.16
- pip version: pip 22.0.4
- `google-cloud-aiplatform` version: 1.24.1

#### Steps to reproduce

1. Create a PipelineJob with a artifact repository URI using a tag instead of the hash
2. Run the pipeline job

#### Code example

This fails with a 500 internal server error on the "run" call.
```python
from google.cloud import aiplatform as aip

service_account = ...
pipeline_name = ...
job_id = f"{pipeline_name}-{datetime.datetime.now().strftime('%Y%m%d%H%M%S')}"

compiled_job = f"https://{region}-kfp.pkg.dev/{PROJECTID}/{REPOSITORY_NAME}/{PIPELINE_NAME}/{TAG}"
pipeline_job = aip.PipelineJob(
display_name="test-name",
job_id=job_id,
template_path=compiled_job,
)

pipeline_job.run(network=None,
service_account=service_account,
sync=True)
```

This runs without problem:

```python
from google.cloud import aiplatform as aip

service_account = ...
pipeline_name = ...
job_id = f"{pipeline_name}-{datetime.datetime.now().strftime('%Y%m%d%H%M%S')}"

compiled_job = f"https://{region}-kfp.pkg.dev/{PROJECTID}/{REPOSITORY_NAME}/{PIPELINE_NAME}/sha:...."
pipeline_job = aip.PipelineJob(
display_name="test-name",
job_id=job_id,
template_path=compiled_job,
)

pipeline_job.run(network=None,
service_account=service_account,
sync=True)
```

#### Stack trace
```
Traceback (most recent call last):
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/google/api_core/grpc_helpers.py", line 72, in error_remapped_callable
return callable_(*args, **kwargs)
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/grpc/_channel.py", line 1030, in __call__
return _end_unary_response_blocking(state, call, False, None)
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/grpc/_channel.py", line 910, in _end_unary_response_blocking
raise _InactiveRpcError(state) # pytype: disable=not-instantiable
grpc._channel._InactiveRpcError: <_InactiveRpcError of RPC that terminated with:
status = StatusCode.INTERNAL
details = "Internal error encountered."
debug_error_string = "UNKNOWN:Error received from peer ipv6:%5B2a00:1450:400e:800::200a%5D:443 {created_time:"2023-05-09T00:09:30.434205595+02:00", grpc_status:13, grpc_message:"Internal error encountered."}"
>

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

Traceback (most recent call last):
File "/home/.../Desktop/test/mlpipelines/monthly_pipeline.py", line 98, in
pipeline_job.run(network=None,
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/google/cloud/aiplatform/pipeline_jobs.py", line 314, in run
self._run(
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/google/cloud/aiplatform/base.py", line 814, in wrapper
return method(*args, **kwargs)
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/google/cloud/aiplatform/pipeline_jobs.py", line 345, in _run
self.submit(
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/google/cloud/aiplatform/pipeline_jobs.py", line 419, in submit
self._gca_resource = self.api_client.create_pipeline_job(
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/google/cloud/aiplatform_v1/services/pipeline_service/client.py", line 1347, in create_pipeline_job
response = rpc(
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/google/api_core/gapic_v1/method.py", line 113, in __call__
return wrapped_func(*args, **kwargs)
File "/home/.../Desktop/test/venv/lib/python3.9/site-packages/google/api_core/grpc_helpers.py", line 74, in error_remapped_callable
raise exceptions.from_grpc_error(exc) from exc
google.api_core.exceptions.InternalServerError: 500 Internal error encountered.
```