To bind to a cloud data source you can provide 00000000-0000-0000-0000-000000000000 as the gateway ID for the bind to gateway API. Found this in an example for the FabricPS-PBIP powershell module (source).

Sample - Deploy semantic model and bind to Shared Cloud Connection (SCC)

$workspaceName = "[Workspace Name]"
$pbipPath = "[PBIP Path]\[Name].SemanticModel"
$connectionsToBind = @("[SCC Connection Id]")

# Authenticate

Set-FabricAuthToken -reset

# Ensure workspace exists

$workspaceId = New-FabricWorkspace  -name $workspaceName -skipErrorIfExists

# Import the semantic model and save the item id

$semanticModelImport = Import-FabricItem -workspaceId $workspaceId -path $pbipPath

# Bind to connections using PowerBI API - no need to specify the datasource, the service automatically maps the datasource to the connection

Write-Host "Binding semantic model to connections"

$authToken = Get-FabricAuthToken

# 'gatewayObjectId' as '00000000-0000-0000-0000-000000000000 indicate the connection is a sharable cloud.

$body = @{
    "gatewayObjectId"= "00000000-0000-0000-0000-000000000000";
    "datasourceObjectIds" = $connectionsToBind
} | ConvertTo-Json

$headers = @{'Content-Type'="application/json"; 'Authorization' = "Bearer $authToken"}

Invoke-RestMethod -Headers $headers -Uri "https://api.powerbi.com/v1.0/myorg/groups/$workspaceId/datasets/$($semanticModelImport.Id)/Default.BindToGateway" -Method Post -Body $body