### Apache Airflow version

2.6.3

### What happened

A task instance's [log_url](https://github.com/apache/airflow/blob/2.6.3/airflow/models/taskinstance.py#L726) does not contain the full URL defined in [base_url](https://github.com/apache/airflow/blob/2.6.3/airflow/models/taskinstance.py#L729C9-L729C69).

### What you think should happen instead

The base_url may contain paths that should be acknowledged when build the log_url. 

The log_url is built with [urljoin](https://docs.python.org/3/library/urllib.parse.html#urllib.parse.urljoin). Due to how urljoin builds URLs, any existing paths are ignored leading to a faulty URL. 

### How to reproduce

This snippet showcases how urljoin ignores existing paths when building the url.

```
>>> from urllib.parse import urljoin
>>> 
>>> 
>>> urljoin(
...     "https://my.astronomer.run/path",
...     f"log?execution_date=test"
...     f"&task_id=wow"
...     f"&dag_id=super"
...     f"&map_index=-1",
... )
'https://eochgroup.astronomer.run/log?execution_date=test&task_id=wow&dag_id=super&map_index=-1'
```

### Operating System

n/a

### Versions of Apache Airflow Providers

_No response_

### Deployment

Astronomer

### Deployment details

_No response_

### Anything else

This was introduced by #31833.

A way to fix this can be to utilize [urlsplit](https://docs.python.org/3/library/urllib.parse.html#urllib.parse.urlsplit) and [urlunsplit](https://docs.python.org/3/library/urllib.parse.html#urllib.parse.urlunsplit) to account for existing paths.

```
from urllib.parse import urlsplit, urlunsplit

parts = urlsplit("https://my.astronomer.run/paths")
urlunsplit((
        parts.scheme,
        parts.netloc,
        f"{parts.path}/log",
        f"execution_date=test"
        f"&task_id=wow"
        f"&dag_id=super"
        f"&map_index=-1",
        ""
    )
)
```

Here is the fix in action.

```
>>> parts = urlsplit("https://my.astronomer.run/paths")
>>> urlunsplit((
...     parts.scheme,
...     parts.netloc,
...     f"{parts.path}/log",
...     f"execution_date=test"
...     f"&task_id=wow"
...     f"&dag_id=super"
...     f"&map_index=-1",
...     ''))
'https://my.astronomer.run/paths/log?execution_date=test&task_id=wow&dag_id=super&map_index=-1'
>>>
>>> parts = urlsplit("https://my.astronomer.run/paths/test")
>>> urlunsplit((
...     parts.scheme,
...     parts.netloc,
...     f"{parts.path}/log",
...     f"execution_date=test"
...     f"&task_id=wow"
...     f"&dag_id=super"
...     f"&map_index=-1",
...     ''))
'https://my.astronomer.run/paths/test/log?execution_date=test&task_id=wow&dag_id=super&map_index=-1'
```

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

name="task_instance_dag_run_fkey",
            ondelete="CASCADE",
        ),
    )
    dag_model = relationship(
        "DagModel",
        primaryjoin="TaskInstance.dag_id == DagModel.dag_id",
        foreign_keys=dag_id,
        uselist=False,
        innerjoin=True,
        viewonly=True,
    )
    trigger = relationship("Trigger", uselist=False, back_populates="task_instance")
    triggerer_job = association_proxy("trigger", "triggerer_job")
    dag_run = relationship("DagRun", back_populates="task_instances", lazy="joined", innerjoin=True)
    rendered_task_instance_fields = relationship("RenderedTaskInstanceFields", lazy="noload", uselist=False)
    execution_date = association_proxy("dag_run", "execution_date")
    task_instance_note = relationship(
        "TaskInstanceNote",
        back_populates="task_instance",
        uselist=False,
        cascade="all, delete, delete-orphan",
    )
    note = association_proxy("task_instance_note", "content", creator=_creator_note)
    task: Operator  
    is_trigger_log_context: bool = False
    """Indicate to FileTaskHandler that logging context should be set up for trigger logging.
    :meta private:
    """
    def __init__(