Disabled fields are included in `getSchemaVariables(..., {inputs: false})`

[marstamm]

Describe the Bug

getSchemaVariables('...', {inputs: false), introduced with v1.1.0, returns variables that will not be in the output

Steps to Reproduce

1. Use the following form:

{
  "components": [
    {
      "label": "Disabled",
      "type": "textfield",
      "layout": {
        "row": "Row_074dkdc",
        "columns": null
      },
      "id": "disabled",
      "key": "disabled",
      "disabled": true,
      "readonly": true
    }
  ],
  "type": "default",
  "id": "Form_0hmakep",
  "executionPlatform": "Camunda Cloud",
  "executionPlatformVersion": "8.2.0",
  "exporter": {
    "name": "Camunda Modeler",
    "version": "5.15.0-nightly.20230815"
  },
  "schemaVersion": 10
}

• The Form output preview in the modeler is empty
• call getSchemaVariables(schema, {inputs: false}) with the schema
• disabled is a return value

Expected Behavior

Disabled fields are not returned

Environment

• Host (Browser/Node version), if applicable: any
• OS: any
• Library version: 1.2.0