fix: fix a number of issues with Labeled and Range Sliders, add LabelsOnHandle mode. (#242)

* fix: remove processEvents

* merge in fixes

* remove comment

* fix hint

* fix napari

* change pyqt6

* fix: fix range slider styles

.github/workflows/test_and_deploy.yml

@@ -32,7 +32,7 @@ jobs:
         exclude:
           # Abort (core dumped) on linux pyqt6, unknown reason
           - platform: ubuntu-latest
-            backend: "'PyQt6<6.6'"
+            backend: pyqt6
           # lack of wheels for pyside2/py3.11
           - python-version: "3.11"
             backend: pyside2
@@ -52,7 +52,7 @@ jobs:
             backend: "'pyside6!=6.6.2'"
           - python-version: "3.12"
             platform: macos-latest
-            backend: "'PyQt6<6.6'"
+            backend: pyqt6
           # legacy Qt
           - python-version: 3.8
             platform: ubuntu-latest