fix(composite): selected row count always 0 on mass-selected

[ghiscoding]

• add dispose method to container service to start with a blank array whenever we route to another page, this is to avoid reusing already disposed services that might still be in the container service
• the issue was found in Angular-Slickgrid and did not seem to show up as a problem in Slickgrid-Universal itself but better play safe and apply the same here

[codecov]

Codecov Report

Merging #712 (0fe7101) into master (1bcf7ad) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #712   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          233       233           
  Lines        16433     16438    +5     
  Branches      5486      5487    +1     
=========================================
+ Hits         16433     16438    +5     

Impacted Files	Coverage Δ
packages/common/src/services/container.service.ts	100.00% <100.00%> (ø)
...bundle/src/components/slick-vanilla-grid-bundle.ts	100.00% <100.00%> (ø)
...-bundle/src/services/universalContainer.service.ts	100.00% <100.00%> (ø)

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