"Examples from AI knowledge base:" should be skipped if there is no example.

## Describe the bug

**Command Name**
`az spring connection update postgres-flexible`

**Errors:**

Besides unrecognized arguments error, it prompts **Azure CLI tries to show examples but nothing.**
```
Examples from AI knowledge base:
https://aka.ms/cli_ref
Read more about the command in reference docs
```

## 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 spring connection update postgres-flexible --resource-group {} --service {} --app {} --connection {} --target-resource-group {} --server {} --database {} --vault-id {}`

## Expected Behavior

## Environment Summary
```
Windows-10-10.0.22621-SP0
Python 3.10.8
Installer: MSI

azure-cli 2.45.0

Extensions:
spring 1.6.6

Dependencies:
msal 1.20.0
azure-mgmt-resource 21.1.0b1
```
## Additional Context