[Reporting] Documentation for Automating Report Generation has legacy example code contents

[tsullivan]

Kibana version: Docs: 7.2

Reporting has outdated documentation on how to integrate Watcher and Reporting: https://www.elastic.co/guide/en/kibana/7.2/automating-report-generation.html.

The page says to "copy and paste the URL from the Kibana UI", however, if instead the user chooses to copy and modify the example URL on the page, it will give them a "legacy" generation URL that is missing API fields.

  "actions" : {
    "email_admin" : { 
      "email": {
        "to": "'Recipient Name <[email protected]>'",
        "subject": "Error Monitoring Report",
        "attachments" : {
          "error_report.pdf" : {
            "reporting" : {
              "url": "http://0.0.0.0:5601/api/reporting/generate/dashboard/Error-Monitoring?_g=(time:(from:now-1d%2Fd,mode:quick,to:now))", 
              "retries":6, 
              "interval":"1s", 
              "auth":{ 
                "basic":{
                  "username":"elastic",
                  "password":"changeme"

The URL should be something more closer to http://0.0.0.0:5601/api/reporting/generate/printablePdf?jobParams=...

[elasticmachine]

Pinging @elastic/kibana-docs

[tsullivan]

Close via #40931