feat: allow using AureliaSlickgrid component w/o grid options

[ghiscoding]

• we should be able to use Aurelia-Slickgrid custom element without providing any grid options

[stackblitz]

Run & review this pull request in StackBlitz Codeflow.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.

Project coverage is 20.91%. Comparing base (b59bf34) to head (3a1cf85).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...slickgrid/src/custom-elements/aurelia-slickgrid.ts	0.00%	5 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1298   +/-   ##
=======================================
  Coverage   20.91%   20.91%           
=======================================
  Files           8        8           
  Lines         952      952           
  Branches      350      327   -23     
=======================================
  Hits          199      199           
  Misses        753      753           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.