Bicep generate-params don't emit optional parameters with --include-params All flag

[olegKoshmeliuk]

Bicep version
Bicep CLI version 0.25.53 (c0ad57d)
Describe the bug
Optional parameters are not emitted by command az bicep generate-params with flag--include-params All

To Reproduce
Create main.bicep file

param productName string = 'testproduct'
param envType string
param sqlServerExists bool =false

run command az bicep generate-params -f main.bicep --stdout --include-params All --output-format json
result output does not contain optional parameters

{
  "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentParameters.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "envType": {
      "value": ""
    }
  }
}

Additional context
This bug reproduced only for JSON format. bicep format is working fine.
VS Code Generate parameters file command also have this bug

main.bicep.txt