It isn't possible to run cell detection on channels with " in the name

[petebankhead]

Bug report

Describe the bug
It isn't possible to run cell detection on channels with " in the name.

This has come up twice on the forum so far:

• https://forum.image.sc/t/error-when-trying-to-run-cell-detection-plugin/62739
• https://forum.image.sc/t/error-in-loading-ome-tiff-images-in-qupath/29758/16

To Reproduce
Steps to reproduce the behavior:

1. Open a fluorescence (non-RGB) image
2. Change a channel name to "DAPI" or similar
3. Try to run cell detection
4. Observe an error - something pretty & informative like5.

Plugin error: com.google.gson.stream.MalformedJsonException: Unterminated object at line 1 column 23 path $.

Expected behavior
A " in a channel name isn't a good idea, but it shouldn't be a deal breaker.

Desktop (please complete the following information):

• OS: All
• QuPath v0.3.2 and earlier

Additional context
The root cause is my dodgy JSON-converting code at https://github.com/qupath/qupath/blob/main/qupath-core/src/main/java/qupath/lib/plugins/parameters/ParameterList.java#L585

Switching to use GsonTools should resolve it, but this will need a bit of care to ensure nothing breaks along the way.