Measure: Fix delta label text size scaling (#21467)

* Measure: Fix delta label font size

- Add font size field to ViewProviderMeasureBase which connects to other fields
- Remove dead code in DimensionLinear which internally is using FrameLabel
- Connect FrameLabels's fontsize property to DimensionLinear's property

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/Mod/Measure/Gui/ViewProviderMeasureBase.h

@@ -88,6 +88,9 @@ public:
     App::PropertyInteger FontSize;
     // NOLINTEND
 
+    // Fields
+    SoSFFloat fieldFontSize;
+
     /**
      * Attaches the document object to this view provider.
      */