Bug in fhemweb.js (SyntaxError: JSON.parse)?

Hi,

I'm using fhem-docker and updated to 3.0.7-bullseye some days ago (and did also updates of other modules).

Since the update I recognized following error when restarting the container while keeping the fhem web page open:

fhemweb.js line 1215:
SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data at line 1 column 5 of the JSON data

I had a quick look at the file /www/pgm2/fhemweb.js: `var d = JSON.parse(l);`
If I understand the code correctly, I guess, there should be another check for the content of `l` before passing it to `JSON.parse()`.

In current main, it's [this line](https://github.com/fhem/fhem-mirror/blob/821b97babed331f75c37fe9f8a20bc6d8789c030/fhem/www/pgm2/fhemweb.js#L1200).
Is this a bug or does that error occure because of some other issue?