Created attachment 1681202 [details]
Alert Graph Timespan Dropdown button

Description of problem:
When testing accessibility with axe, we get the following error:
[
  {
    "data": "",
    "id": "button-has-visible-text",
    "impact": "critical",
    "message": "Element does not have inner text that is visible to screen readers",
    "relatedNodes": [
      {
        "html": "<button aria-haspopup="true" aria-expanded="false" class="pf-c-dropdown__toggle dropdown-button--icon-only" data-test-id="dropdown-button" type="button">"
      }
    ]
  }
]

Appeared in this location: http://localhost:9000/monitoring/alerts/4212693293?alertname=KubePodNotReady&namespace=default&pod=example-0&severity=critical
However, I believe I was able to reproduce it by going to Alerting under Monitoring then selecting an alert. 


How reproducible:
Easily reproducible with the axe browser extension.

Steps to Reproduce:
1. Go to alerting under monitoring, select an alert
2. Open developer tools, go to the axe tab, press analyze
3. Click on the issue "Buttons must have discernible text" for details

Actual results:
The dropdown button is inaccessible by screen reader, the user is unable to tell what the button does at the moment. If you open up VO, it just reads it as "collapsed, pop up button" instead of explaining what the button does.


Expected results:
The button should have a label accessible by screen reader that clearly describes what the action does.Additional info: