Cannot read property 'replace' of undefined

### Description

how did I use it

in the head tag

` `

and in the body
```

{
"vars": {
"account": "UA-XXXXXX-1"
},
"triggers": {
"trackPageview": {
"on": "visible",
"request": "title_page"
}
}
}

```

index.js:108 Uncaught (in promise) TypeError: Cannot read property 'replace' of undefined
at ta (index.js:108)
at pf (amp-analytics.js:546)
at lf.push.f.l.ed (amp-analytics.js:291)

### Reproduction Steps

check online demo there
[https://mkaleh.com/category/%D8%B4%D8%A4%D9%88%D9%86_%D9%85%D9%86%D8%B2%D9%84%D9%8A%D8%A9](url)

### Relevant Logs

_No response_

### Browser(s) Affected

_No response_

### OS(s) Affected

_No response_

### Device(s) Affected

_No response_

### AMP Version Affected

_No response_

Reproduce the error using the linked demo and the AMP Analytics configuration in the issue. Start at index.js:108 and the amp-analytics.js stack locations around lines 546 and 291, then confirm the undefined value and verify that the reported configuration no longer throws the replace error.

Written by the indexing model from the issue text.