Fix missing representation of layer's custom property list in the info page (HtmlMetadata)

[signedav]

This covers lists and in only one level deepness.

Other types that cannot be converted to a string or a stringlist are not represented (by the text value cannot be displayed).

("weirdoType" is manually added with type "Map")

It probably makes sense to have a more powerful representation, but then I suggest to go deeper into the content like proposed here #57335 But this is IMHO an extension and not scope of this small "fix" here.

This fixes #57334

[signedav]

Is this what you imagine @DelazJ ?
Does the implementation make sense for you @jadsilva ?

[github-actions]

🪟 Windows builds ready!

Windows builds of this PR are available for testing here. Debug symbols for this build are available here.

(Built from commit 351b955)

[DelazJ]

Is this what you imagine @DelazJ ?

Yes because now the variables are all displayed so the bug is fixed. Thanks @signedav
No 😄 because the matching variable name <-> value is not necessarily obvious, and assuming I understood your suggestion, displaying the variables name/value next to each other in a table would provide a better user experience. For the next step?

[signedav]

displaying the variables name/value next to each other in a table would provide a better user experience. For the next step?

Yes exactly, I think it would make sense to improve the UX there in another (independent) step, but I would like to have this here as a fix of the bug, that the values are not displayed at all...

[signedav]

Thanks @nyalldawson Now it evaluates the QMetaType according to the Qt version and makes the conversion according to it.