text: Title: Allure report showing NaN% while using --device matrix capability in Json format
  Body: Hi Team,
  
  I am facing issue to generate allure report using allure-pytest-bdd 2.9.45 version. We are passing browser capabilities by using Json file.
  [
      {
          "local" : "true",
          "browser": "Chrome",
          "driver_path": "./binaries/webdriver/chromedriver",
          "resolution": "1900x1100",
          "headless": "true"
      }
  ]
  
  python -m pytest -v --gherkin-terminal-reporter --tags "$TAGS" -n "$THREADS" --device-matrix "$CONFIG_JSON_FILE" --alluredir=output/reports/allure-results
  
  It is creating extra dictionary in the allure json file due to which report is showing NaN%
  ![image](https://user-images.githubusercontent.com/93395588/161532457-1ee2f848-da90-4d39-9075-e879ef514268.png)
  
  Json Result - 
  {
     "name":"Navigate to championspfizercom with proxy enabled [chrome]",
     "status":"passed",
     "steps":[
        {
           "name":"Given The browser resolution is '1367' per '768'",
           "status":"passed",
           "start":1648644612533,
           "stop":1648644615274
        },
        {
           "name":"Given I am on the url 'https://championspfizercom-preview.dev.pfizerstatic.io/'",
           "status":"passed",
           "start":1648644615276,
           "stop":1648644617743
        },
        {
           "name":"Then I expect that the title is not 'Sign in ・ Cloudflare Access'",
           "status":"passed",
           "start":1648644617749,
           "stop":1648644627957
        },
        {
           "name":"And I expect that the title is 'Alliance Anticoagulation Foundation | Homepage'",
           "status":"passed",
           "start":1648644627974,
           "stop":1648644627981
        }
     ],
     **"parameters":[
        {
           "name":"custom_browser_config",
           "value":{
              "local":"true",
              "browser":"Chrome",
              "driver_path":"./binaries/webdriver/chromedriver",
              "headless":"true"
           }
        }**
     ],
     "start":1648644612528,
     "stop":1648644627982,
     "uuid":"1fae8e62-a32d-b230-6436-801757483f67",
     "historyId":"1fae8e62a32db2306436801757483f67",
     "fullName":"features\\proxy.feature:Navigate to championspfizercom with proxy enabled",
     "labels":[
        {
           "name":"host",
           "value":"DESKTOP-7MNDH5C"
        },
        {
           "name":"thread",
           "value":"13280-MainThread"
        },
        {
           "name":"framework",
           "value":"pytest-bdd"
        },
        {
           "name":"language",
           "value":"cpython3"
        },
        {
           "name":"feature",
           "value":"Tests to verify proxy config"
        }
     ]
  }
  
  #### I'm submitting a ... 
    - [ ] bug report
  
  #### What is the current behavior?
  
  
  #### If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem
  
  
  #### What is the expected behavior?
  
  
  #### What is the motivation / use case for changing the behavior?
  
  
  #### Please tell us about your environment:
  
  - Allure version:        2.1.0
  - Test framework:        pytest@3.9.7
  - Allure adaptor:        allure-pytest-bdd@2.9.45
  
  Kindly Advice.
  