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

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

src/Mod/Measure/Gui/ViewProviderMeasureBase.cpp

@@ -194,6 +194,7 @@ ViewProviderMeasureBase::ViewProviderMeasureBase()
     TextBackgroundColor.touch();
     FontSize.touch();
     LineColor.touch();
+    fieldFontSize.setValue(FontSize.getValue());
 }
 
 ViewProviderMeasureBase::~ViewProviderMeasureBase()
@@ -251,6 +252,7 @@ void ViewProviderMeasureBase::onChanged(const App::Property* prop)
     }
     else if (prop == &FontSize) {
         pLabel->size = FontSize.getValue();
+        fieldFontSize.setValue(FontSize.getValue());
     }
     ViewProviderDocumentObject::onChanged(prop);
 }