fix: Serverfarm: Disable AZ PSRule rule as not available in AVM subsc…

…ription (Azure#3177)

## Description

The module implements a logic that automatically enables zones in a
premium SKU is used. Those SKUs are unfortunately not available in the
AVM subscription which is why we have to deploy the service in a
standard SKU. Because that's not aligned with PSRule we have to disable
the test in the PSRule settings.

## Pipeline Reference

<!-- Insert your Pipeline Status Badge below -->

| Pipeline |
| -------- |
|
[![avm.res.web.serverfarm](https://github.com/Azure/bicep-registry-modules/actions/workflows/avm.res.web.serverfarm.yml/badge.svg?branch=users%2Falsehr%2FserverFarmReliability&event=workflow_dispatch)](https://github.com/Azure/bicep-registry-modules/actions/workflows/avm.res.web.serverfarm.yml)
|

## Type of Change

<!-- Use the checkboxes [x] on the options that are relevant. -->

- [x] Update to CI Environment or utilities (Non-module affecting
changes)
- [ ] Azure Verified Module updates:
- [ ] Bugfix containing backwards-compatible bug fixes, and I have NOT
bumped the MAJOR or MINOR version in `version.json`:
- [ ] Someone has opened a bug report issue, and I have included "Closes
#{bug_report_issue_number}" in the PR description.
- [ ] The bug was found by the module author, and no one has opened an
issue to report it yet.
- [ ] Feature update backwards compatible feature updates, and I have
bumped the MINOR version in `version.json`.
- [ ] Breaking changes and I have bumped the MAJOR version in
`version.json`.
  - [ ] Update to documentation

avm/utilities/pipelines/staticValidation/psrule/ps-rule.yaml

@@ -81,3 +81,4 @@ rule:
     - Azure.VM.UseHybridUseBenefit
     - Azure.AppConfig.PurgeProtect
     - Azure.MySQL.MaintenanceWindow # Must be excluded until https://msdata.visualstudio.com/Database%20Systems/_workitems/edit/2788114 is fixed
+    - Azure.AppService.AvailabilityZone # Must disable as the serverfarm premium skus are not available in the AVM subscription. The module is WAF-aligned, just the tests don't validate it