after upgrading to 6.0.0 the embedding dashboarding is broken

### Bug description

4.1.4 embedding was working fine with guest token but after upgrading to 6.0.0 it is broken

In 4.1.4 the emedding dashboarding was working fine with superset. But recently we have upgraded our superset to 6.0.0 version it is giving below error.

{
"errors": [
{
"message": "403 Forbidden: You don't have the permission to access the requested resource. It is either read-protected or not readable by the server.",
"error_type": "GENERIC_BACKEND_ERROR",
"level": "error",
"extra": {
"issue_codes": [
{
"code": 1011,
"message": "Issue 1011 - Superset encountered an unexpected error."
}
]
}
}
]
}

**getting above error after hitting the our domain instead of reports it is showing above error**

### Screenshots/recordings

In 4.1.4 the emedding dashboarding was working fine with superset. But recently we have upgraded our superset to 6.0.0 version it is giving below error.

{
"errors": [
{
"message": "403 Forbidden: You don't have the permission to access the requested resource. It is either read-protected or not readable by the server.",
"error_type": "GENERIC_BACKEND_ERROR",
"level": "error",
"extra": {
"issue_codes": [
{
"code": 1011,
"message": "Issue 1011 - Superset encountered an unexpected error."
}
]
}
}
]
}

**getting above error after hitting the our domain instead of reports it is showing above error**

### Superset version

6.0.0

### Python version

3.10

### Node version

18 or greater

### Browser

Chrome

### Additional context

_No response_

### Checklist

- [ ] I have searched Superset docs and Slack and didn't find a solution to my problem.
- [ ] I have searched the GitHub issue tracker and didn't find a similar bug report.
- [ ] I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.

No source files or tests are named. Start by reproducing embedded dashboard access on Superset 6.0.0 with a guest token, compare it with 4.1.4, and inspect the server logs around the 403 response and issue code 1011. Done means identifying the permission regression or configuration difference and confirming that the embedded dashboard loads through the domain.

Written by the indexing model from the issue text.