[O2B-1083] Fix a bug in LHC overview pages, now displaying missing dates as '-' instead of the default epoch time (#1298)

Author: SandroBoelsz

lib/database/adapters/LhcFillAdapter.js

@@ -49,8 +49,8 @@ class LhcFillAdapter {
 
         return {
             fillNumber,
-            stableBeamsStart: new Date(stableBeamsStart).getTime(),
-            stableBeamsEnd: new Date(stableBeamsEnd).getTime(),
+            stableBeamsStart: stableBeamsStart ? new Date(stableBeamsStart).getTime() : stableBeamsStart,
+            stableBeamsEnd: stableBeamsEnd ? new Date(stableBeamsEnd).getTime() : stableBeamsEnd,
             stableBeamsDuration,
             beamType,
             fillingSchemeName,