[REGRESSION]: AzureFunctionApp@1 has a bug in appSettings parsing

[LouOtway]

New issue checklist

• I searched for existing GitHub issues
• I read pipeline troubleshooting guide
• I checked how to collect logs

Task name

AzureFunctionApp@1

Breaking task version

No response

Last working task version

No response

Regression Description

A regression happened!

[](#15481)

Environment type (Please select at least one enviroment where you face this issue)

• Self-Hosted
• Microsoft Hosted
• VMSS Pool
• Container

Azure DevOps Server type

dev.azure.com (formerly visualstudio.com)

Azure DevOps Server Version (if applicable)

No response

Operation system

Ubuntu

Relevant log output

Starting: Deploy to Dev
==============================================================================
Task         : Azure Functions
Description  : Update a function app with .NET, Python, JavaScript, PowerShell, Java based web applications
Version      : 1.259.1
Author       : Microsoft Corporation
Help         : https://aka.ms/azurefunctiontroubleshooting
==============================================================================
Got service connection details for Azure App Service:'maslo-d365integration-dev-uks-fas'
NOTE: Function app has private endpoint(s). Therefore, make sure that you are running this pipeline from a self-hosted agent that has access to the Functions App.
NOTE: Function app is VNet integrated.
Updating App Service Application settings. Data: {"WEBSITE_RUN_FROM_PACKAGE":"1"}
Deleting App Service Application settings. Data: ["WEBSITE_RUN_FROM_ZIP"]
App Service Application settings are already present.
Validating deployment package for functions app before Zip Deploy
Package deployment using ZIP Deploy initiated.
Deploy logs can be viewed at https://REDACTED.azurewebsites.net/api/deployments/REDACTED/log
The web package has been deployed to App Service. Please note that the package mount or extraction errors will be logged in the deployment logs in the location above.
NOTE: Run From Package makes wwwroot read-only, so you will receive an error when writing files to this directory.
Updating App Service Application settings. Data: {"ClientId":"REDACTED","ClientSecret":"REDACTED\nTenantId","":"web-integration"}
##[error]Error: Failed to update App service 'REDACTED' application settings. Error: BadRequest - Parameter name cannot be empty. (CODE: 400)
App Service Application URL: https://REDACTED.azurewebsites.net
Finishing: Deploy to Dev

Full task logs with system.debug enabled

UNSUCCESSFUL RUN

 [REPLACE THIS WITH YOUR INFORMATION] 

SUCCESSFUL RUN

 [REPLACE THIS WITH YOUR INFORMATION] 

Repro steps