fix(gridMenu): command "Toggle Filter Row" header row

[ghiscoding]

previous PR #448 caused a new and small issue, were the header row is being shown when changing locale even when there are no Filters.

[codecov]

Codecov Report

Merging #466 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##            master      #466    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files          148       148            
  Lines         9534      9534            
  Branches      3314      3177   -137     
==========================================
  Hits          9534      9534            

Impacted Files	Coverage Δ
...lickgrid/components/angular-slickgrid.component.ts	100.00% <100.00%> (ø)
...r-slickgrid/services/groupingAndColspan.service.ts	100.00% <100.00%> (ø)

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