Mark AMA ext as not supported on suse_15

[maddieford]

Description

AMA is consistently failing on suse 15 with the following error:
{
"code": "VMExtensionHandlerNonTransientError",
"target": "0",
"message": "The handler for VM extension type 'Microsoft.Azure.Monitor.AzureMonitorLinuxAgent' has reported terminal failure for VM extension 'AzureMonitorLinuxAgent' with error message: '[ExtensionOperationError] Non-zero exit code: 104, /var/lib/waagent/Microsoft.Azure.Monitor.AzureMonitorLinuxAgent-1.33.1/./shim.sh -install\n[stdout]\n2025/01/17 13:43:46 No provider of 'insserv-compat' found.\n\n\n[stderr]\n'.\r\n \r\n'Install handler failed for the extension. More information on troubleshooting is available at https://aka.ms/vmextensionlinuxtroubleshoot'"
}
]
}
}

Several tests are already skipped on a set of distros due to lack of AMA support. Add suse 15 to this set of distros.

Issue #

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