fix(extensions): import jQuery mousewheel only with frozen, fixes #618

[ghiscoding]

• when jQuery mousewheel is imported, SlickGrid attaches a scroll handler which prevent scrolling to work as normal, this however should only be used with frozen grids since it creates other issues like seen in Row Detail were it doesn't behave correctly
• NOTE that this is more of a patch and a SlickGrid grid option flag would be better to handle that, possibly create a flag in future SlickGrid version
• fixes Mousewheel event in row detail #618

[codecov]

Codecov Report

Merging #619 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #619   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          149       149           
  Lines         9980      9983    +3     
  Branches      3527      3529    +2     
=========================================
+ Hits          9980      9983    +3     

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

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