astrodatagui: disable normalize if we combine fits files

reason: crash due to different units of flux and flux_err for most
fits files

main/astrodatagui/AstrodataGUI.py

@@ -176,6 +176,7 @@ class AstrodataGUI(QtWidgets.QMainWindow):
 
     def sequenceSelected(self, item):
         self.gbPlotOptions.setEnabled(True)
+        self.gbPlotOptionsNormalize.setEnabled(True)
         seqText = item.text().split(" - ")
         mainName = self.listDownloaded.currentItem().text()
         source = seqText[0]
@@ -184,6 +185,7 @@ class AstrodataGUI(QtWidgets.QMainWindow):
         self.flaredetectorPreview.setFitsFile(filePath, mainName)
 
     def btCombineSeqClicked(self):
+        self.gbPlotOptionsNormalize.setEnabled(False)
         mainName = self.listDownloaded.currentItem().text()
         filePaths = []
         for item in self.listSequences.selectedItems():

main/astrodatagui/astrodatagui.ui

@@ -298,7 +298,7 @@
                  <item>
                   <layout class="QVBoxLayout" name="verticalLayout_7">
                    <item>
-                    <widget class="QGroupBox" name="groupBox_7">
+                    <widget class="QGroupBox" name="gbPlotOptionsNormalize">
                      <property name="sizePolicy">
                       <sizepolicy hsizetype="Preferred" vsizetype="Maximum">
                        <horstretch>0</horstretch>