[Backport to 5.7] The Azure ManagementUrl setting accepts URLs without a trailing forward slash

[johnsimons]

Symptoms

You are affected by this issue, if you have set the Azure Management Url setting to a valid url, but are getting this error in the diagnostics tab in ServicePulse:

Management url configuration is invalid, available options are "https://management.azure.com/", "https://management.microsoftazure.de/", "https://management.usgovcloudapi.net/", "https://management.chinacloudapi.cn/"

Who's affected

Customers that have manually added an Azure Management Url setting, and did not add the last forward slash to the url, for example https://management.azure.com

Root cause

The logic did not cater for url without the last slash so urls like https://management.azure.com/ and https://management.azure.com did not match.