Set-AzSynapseLinkedService Overriding Azure Function Auth Method

### Description

**Possible Similar Support Issues**
This may be the same issue as [Issue 21930](https://github.com/Azure/azure-powershell/issues/21930)
**Summary**
While invoking "Set-AzSynapseLinkedService" against an Azure Function linked service, using the System Assigned Managed Identity authentication type in the source reference file, the command succeeds and correctly deploys everything in the source code definition file, but overrides the authentication type with "Anonymous". instead of the correct authentication method value in the definition file of "MSI"
**Command**
`Set-AzSynapseLinkedService -WorkspaceName -Name -DefinitionFile `
**Definition File Json**
**Output**

### Issue script & Debug output

```PowerShell
Set-AzSynapseLinkedService -WorkspaceName -Name -DefinitionFile
```

### Environment data

```PowerShell
PS C:\WINDOWS\system32> $PSVersionTable

Name Value
---- -----
PSVersion 5.1.17763.4644
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
BuildVersion 10.0.17763.4644
CLRVersion 4.0.30319.42000
WSManStackVersion 3.0
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
```

### Module versions

```PowerShell
ModuleType Version Name ExportedCommands
---------- ------- ---- ---------------
Script 2.12.5 Az.Accounts {Disable-AzDataCollection, Disable-AzContextAutosave, Enab...
Script 2.2.0 Az.Synapse {Get-AzSynapseSparkJob, Stop-AzSynapseSparkJob, Submit-AzS...
```

### Error output

```PowerShell
No error output, succeeds and correctly deploys everything else in the source code definition file, but overrides authentication method with Anonymous (see screenshots).
```