Dispose all cell editors of the PCA samples table

[akurtakov]

SamplesListUI created one SamplesEditingSupport per editable column but kept only the last one, so the ColorCellEditor and its preview image were never disposed. The dispose() override in AnalysisEditorUI that was meant to clean up is not called when the part closes and also skipped super.dispose().

Keep all editing supports and dispose them when the table is disposed.

Assisted-by: Anthropic Claude Code (claude-opus-5-5[1m])

[akurtakov]

Fixes disposal problems in the log:

(OpenChrom (Hillenkamp):1999092): Gtk-WARNING **: 08:50:46.032: gtk_widget_size_allocate(): attempt to allocate widget with width -5 and height 0
java.lang.Error: SWT Resource was not properly disposed
    at org.eclipse.swt.graphics.Resource.initNonDisposeTracking(Resource.java:191)
    at org.eclipse.swt.graphics.Resource.<init>(Resource.java:124)
    at org.eclipse.swt.graphics.Image.<init>(Image.java:508)
    at org.eclipse.jface.viewers.ColorCellEditor.updateContents(ColorCellEditor.java:235)
    at org.eclipse.jface.viewers.DialogCellEditor.doSetValue(DialogCellEditor.java:311)
    at org.eclipse.jface.viewers.ColorCellEditor.<init>(ColorCellEditor.java:132)
    at org.eclipse.jface.viewers.ColorCellEditor.<init>(ColorCellEditor.java:118)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.internal.provider.SamplesEditingSupport.<init>(SamplesEditingSupport.java:44)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.swt.SamplesListUI.setEditingSupport(SamplesListUI.java:93)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.swt.SamplesListUI.createColumns(SamplesListUI.java:82)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.swt.SamplesListUI.<init>(SamplesListUI.java:49)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.swt.AnalysisEditorUI.createSampleListUI(AnalysisEditorUI.java:604)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.swt.AnalysisEditorUI.createSamplesSection(AnalysisEditorUI.java:354)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.swt.AnalysisEditorUI.createDataTab(AnalysisEditorUI.java:340)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.swt.AnalysisEditorUI.createControl(AnalysisEditorUI.java:165)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.swt.AnalysisEditorUI.<init>(AnalysisEditorUI.java:112)
    at org.eclipse.chemclipse.xxd.process.supplier.pca.ui.editors.PCAEditor.createControl(PCAEditor.java:60)