[Azure Application Insights Integration] Update doc (fix Microsoft link)

Need to update the Azure Application Insights Integration doc fixing the '[Azure Monitor Log Analytics API Overview](https://dev.applicationinsights.io/documentation/Authorization/API-key-and-App-ID)' link which is currently returning 404.

[https://github.com/elastic/integrations/tree/main/packages/azure_application_insights#integration-level-configuration-options](https://github.com/elastic/integrations/tree/main/packages/azure_application_insights#integration-level-configuration-options)

New link: [https://learn.microsoft.com/en-us/azure/azure-monitor/logs/api/access-api](https://learn.microsoft.com/en-us/azure/azure-monitor/logs/api/access-api)