[Reference feedback]: az monitor metrics alert | update `--evaluation-frequency` description to provide acceptable values

### Type of issue

Missing information

### Reference command name

az monitor metrics alert

### Feedback

This GitHub issues originated in UUF [40080](https://dev.azure.com/msft-skilling/Content/_workitems/edit/400080).

### Request to engineering
Add the acceptable values for `--evaluation-frequency` in the `short-summary` of the source code.

### Customer verbatim
The Window-size and evaluation-frequency is limited to 1m, 5m, 15m, 30m, 1h, 6h, 12h, 1D. Please add those constraints in the doc.

### Verbatim Id:
ee154950-59f0-ef11-9341-000d3a302218

### UUF Triage App Feedback URL:
https://aka.ms/UUFTriageApp?pageviewid=3d3ec0ce-42c7-3520-87d4-d2ff2c33ec43

### Page URL

https://learn.microsoft.com/en-us/cli/azure/monitor/metrics/alert

### Content source URL

https://github.com/MicrosoftDocs/azure-docs-cli/blob/live/latest/docs-ref-autogen/monitor/metrics/alert.yml

### Author

_No response_

### Document Id

_No response_