Execute Flow while viewing a list item

I've configured the layout for the list item header to use the JSON below: 

{
"$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
"elmType": "button",
"txtContent": "Generate PDF",
"customRowAction": {
"action": "executeFlow",
"actionParams": "{\"id\": \"************************************\"}"
},
"attributes": {
"class": "ms-fontColor-themePrimary ms-fontColor-themeDarker--hover"
},
"style": {
"background-color": "#008082",
"border":"1px solid #008082",
"color":"white",
"cursor": "pointer",
"margin-top":"15px"
}
}

However, when I click on an item to view it then click on the "Generate PDF" button it will not run the flow:

I've also tried to go into the list's settings and applied the same JSON to a "Generate PDF" single line of text column that I created. The flow will run if I click on the "Generate PDF" button while in the All Items view, but I'm looking to have the flow run while viewing a single item in the list like in the screenshot above. Is this possible? If so, what am I doing wrong?

I know it's possible to accomplish this with a Power App, however, Power Apps does not support the table formatting added to rich-text enabled columns.