Also catch IndexError for numpy array access with bool

v1.12 of numpy raises an IndexError of a scalar boolean is
given to access an array but this was reverted in later
versions. The behaviour should be essentially the same
as there is no mask so we add it to the existing exception
list.
Refs #27994

qt/python/mantidqt/widgets/colorbar/colorbar.py

@@ -195,7 +195,7 @@ class ColorbarWidget(QWidget):
                 try:
                     self.cmin_value = data[~data.mask].min()
                     self.cmax_value = data[~data.mask].max()
-                except AttributeError:
+                except (AttributeError, IndexError):
                     self.cmin_value = np.nanmin(data)
                     self.cmax_value = np.nanmax(data)
             except (ValueError, RuntimeWarning):