Years available query fails in some cases in heatmap views

• Selecting a year omits links to other years
• When selecting new year and no checks are available

Sentry Issue: WAVEQC-11

IndexError: too many indices for array: array is 1-dimensional, but 3 were indexed
(10 additional frame(s) were not displayed)
...
  File "waveqc/views.py", line 297, in network_detail
    "figure": self.figure(results=results, items=stations, dates=dates),
  File "waveqc/views.py", line 120, in figure
    z=results[:, :, 0] + results[:, :, 1],