Add guard for global.navigation in Column.jsx

[PMByrne]

Because the Column.jsx is making use of global.navigator without any guard, you cannot shallow render any component that imports react-redux-grid.

This means that you have to mock out any imports of react-redux-grid to test the components that wrap them.

Simply adding a check for navigator allows the parent component that imports react-redux-grid to be shallowly rendered and tested.

Another possible solution would be to run the check each time Column.render is called but I didn't go this route to preserve the current performance characteristic of the current isChrome check.

[codecov-io]

Codecov Report

Merging #183 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #183   +/-   ##
=======================================
  Coverage   75.98%   75.98%           
=======================================
  Files         112      112           
  Lines        5143     5143           
  Branches      366      366           
=======================================
  Hits         3908     3908           
  Misses        958      958           
  Partials      277      277

Impacted Files	Coverage Δ
src/components/layout/header/Column.jsx	78.03% <100%> (ø)	⬆️

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