az aks install-cli --kubelogin-base-src-url is not using provided destination to lookup latest version

### Describe the bug

For Azure China AKS operations, it is common to use binaries such as kubectl and kubelogin. However, github is not availble in China, and instead we use the Kubernetes mirror in China: https://mirror.azure.cn/kubernetes/

For instance, we use the following command in our pipelines
```bash
az aks install-cli --base-src-url https://mirror.azure.cn/kubernetes/kubectl --kubelogin-base-src-url https://mirror.azure.cn/kubernetes/kubelogin
```
This command, for kubectl, uses the destination provided by the command line to lookup the latest.txt:

No version specified, will get the latest version of kubectl from "**https://mirror.azure.cn/kubernetes/kubectl/stable.txt**"

However, it is not done for kubelogin:
```bash
No version specified, will get the latest version of kubelogin from "https://api.github.com/repos/Azure/kubelogin/releases/latest"
Downloading client to "C:\Users\myuser\AppData\Local\Temp\tmp6b19jvjy\kubelogin.zip" from "https://mirror.azure.cn/kubernetes/kubelogin/v0.1.7/kubelogin.zip"
Connection error while attempting to download client (HTTP Error 404: Not Found)
```

The file does exist: https://mirror.azure.cn/kubernetes/kubelogin/latest but the az cli is looking for the github releases. This causes an issue because the mirror does not have the latest version.

### Related command

az aks install-cli

### Errors

No version specified, will get the latest version of kubelogin from "https://**api.github.com/repos/Azure/kubelogin/releases/latest**"
Downloading client to "C:\Users\myuser\AppData\Local\Temp\tmp6b19jvjy\kubelogin.zip" from "https://mirror.azure.cn/kubernetes/kubelogin/v0.1.7/kubelogin.zip"
Connection error while attempting to download client (HTTP Error 404: Not Found)

### Issue script & Debug output

```
cli.azure.cli.command_modules.acs.custom: No version specified, will get the latest version of kubelogin from "https://api.github.com/repos/Azure/kubelogin/releases/latest"
cli.azure.cli.command_modules.acs.custom: Downloading client to "C:\Users\marce\AppData\Local\Temp\tmpmhitqm08\kubelogin.zip" from "https://mirror.azure.cn/kubernetes/kubelogin/latest/v0.1.7/kubelogin.zip"
cli.azure.cli.core.azclierror: Traceback (most recent call last):
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/command_modules/acs/custom.py", line 1991, in k8s_install_kubelogin
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/command_modules/acs/custom.py", line 2038, in _urlretrieve
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/command_modules/acs/custom.py", line 2033, in _urlopen_read
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/command_modules/acs/custom.py", line 2024, in _urlopen_read
File "urllib\request.py", line 215, in urlopen
File "urllib\request.py", line 521, in open
File "urllib\request.py", line 630, in http_response
File "urllib\request.py", line 559, in error
File "urllib\request.py", line 492, in _call_chain
File "urllib\request.py", line 639, in http_error_default
urllib.error.HTTPError: HTTP Error 404: Not Found

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\knack/cli.py", line 233, in invoke
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 666, in execute
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 734, in _run_jobs_serially
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 703, in _run_job
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 336, in __call__
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/command_operation.py", line 120, in handler
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/command_modules/acs/custom.py", line 1748, in k8s_install_cli
File "D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/command_modules/acs/custom.py", line 1993, in k8s_install_kubelogin
knack.util.CLIError: Connection error while attempting to download client (HTTP Error 404: Not Found)

cli.azure.cli.core.azclierror: Connection error while attempting to download client (HTTP Error 404: Not Found)
az_command_data_logger: Connection error while attempting to download client (HTTP Error 404: Not Found)
cli.knack.cli: Event: Cli.PostExecute []
```

### Expected behavior

The kubelogin installer should lookup https://mirror.azure.cn/kubernetes/kubelogin/latest which is the --kubelogin-base-src-url value with /latest appended to it.

### Environment Summary

```
azure-cli 2.68.0

core 2.68.0
telemetry 1.1.0

Extensions:
aks-preview 13.0.0b2

Dependencies:
msal 1.31.1
azure-mgmt-resource 23.1.1

Python location 'C:\Program Files\Microsoft SDKs\Azure\CLI2\python.exe'
Extensions directory 'C:\Users\marce\.azure\cliextensions'

Python (Windows) 3.12.8 (tags/v3.12.8:2dc476b, Dec 3 2024, 19:30:04) [MSC v.1942 64 bit (AMD64)]

Legal docs and information: aka.ms/AzureCliLegal

Your CLI is up-to-date.
```

### Additional context

I have created the issue here: https://github.com/Azure/container-service-for-azure-china/issues/75 for the lack of up to date files in the china mirror.