Move label generating logic in a separate method in DC_ProductData

[ameotoko]

Fixes #2340

[aschempp]

Is this intending to replace the method in Contao 4.13 and already use it in Contao 4.9? Do we really need to fix our own method or shouldn't the original issue be fixed in the Contao core method (of 4.13)?

[ameotoko]

There's nothing to fix in Contao, Isotope uses custom driver with some custom logic in listView(), regarding list labels rendering. To be also compatible with 4.13, that logic needs to be available as a separate method.

That's exactly and only thing this PR does – it moves the block of code into a separate method. Does not break anything in 4.9.

[ameotoko]

Any thoughts @aschempp?

[aschempp]

Thank you @ameotoko! Finally got around to finish this. Now that we have Contao 4.13 this also got much easier 🙃