SPTrustedIdentityTokenIssuer: Impossible to use "MetadataEndPoint" parameter

Details of the scenario you tried and the problem that is occurring

I am trying to use MetadataEndPoint because I want SharePoint to extract certificate so I don't have to obtain it manually and specify in "SigningCertificateFilePath" in the DSC resource.

Verbose logs showing the problem

N/A

Suggested solution to the issue

Implement parameter set with "MetadataEndPoint"

The DSC configuration that is used to reproduce the issue (as detailed as possible)

# insert configuration here

The operating system the target node is running

OsName               : Microsoft Windows Server 2019 Datacenter
OsOperatingSystemSKU : DatacenterServerEdition
OsArchitecture       : 64-bit
WindowsVersion       : 1809
WindowsBuildLabEx    : 17763.1.amd64fre.rs5_release.180914-1434
OsLanguage           : en-US
OsMuiLanguages       : {en-US}

Version of SharePoint that is used (e.g. SharePoint 2016)

SharePoint 2019

Version and build of PowerShell the target node is running

Name                           Value
----                           -----
PSVersion                      5.1.17763.316
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.17763.316
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Version of the DSC module that was used ('dev' if using current dev branch)

3.1

Start at the SPTrustedIdentityTokenIssuer DSC resource and inspect how its parameter sets handle MetadataEndPoint and SigningCertificateFilePath. Reproduce the SharePoint 2019 configuration with MetadataEndPoint, then verify that the resource accepts the parameter and obtains the signing certificate without requiring SigningCertificateFilePath.