az commands should not offer to upgrade on every call until the feature works

### **This is autogenerated. Please review and update as needed.**

## Describe the bug

**Command Name**
`az upgrade`

**Errors:**
```
The command failed with an unexpected error. Here is the traceback:
[WinError 2] The system cannot find the file specified
Traceback (most recent call last):
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\knack/cli.py", line 231, in invoke
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 657, in execute
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 720, in _run_jobs_serially
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 691, in _run_job
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 328, in __call__
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/command_operation.py", line 121, in handler
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/command_modules/util/custom.py", line 135, in upgrade_version
File "subprocess.py", line 340, in call
File "subprocess.py", line 858, in __init__
File "subprocess.py", line 1311, in _execute_child
FileNotFoundError: [WinError 2] The system cannot find the file specified

```

## To Reproduce:
Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

- _Put any pre-requisite steps here..._
- `az upgrade`

## Expected Behavior

## Environment Summary
```
Windows-10-10.0.19041-SP0
Python 3.8.9
Installer: MSI

azure-cli 2.23.0 *

Extensions:
storage-preview 0.7.2

```
## Additional Context
Every `az` command shows
```
This command is in preview and under development. Reference and support levels: https://aka.ms/CLI_refstatus
Your current Azure CLI version is 2.23.0. Latest version available is 2.24.2.
Please check the release notes first: https://docs.microsoft.com/cli/azure/release-notes-azure-cli
Do you want to continue? (Y/n): Y
```
after execution. However the upgrade doesn't work. This message should be removed until the feature works more than 0% of the time.