Preventing range selection from triggering when element inside CellTemplate is clicked - 20.0.x

[IvanKitanov17]

Closes #15810

Additional information (check all that apply):

• Bug fix
• New functionality
• Documentation
• Demos
• CI/CD

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code (test guidelines)
• This PR includes API docs for newly added methods/properties (api docs guidelines)
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes (migrations guidelines)
• This PR includes behavioral changes and the feature specification has been updated with them

[RivaIvanova]

@IvanKitanov17
Currently, the hierarchical grid fires selected and rangeSelected on any click (clicking on a templated cell or not). You should add && !event.target.closest('igx-hierarchical-grid-cell') as well. This should resolve the issue with the rangeSelected event being fired, and I will log the behavior of the selected event in a separate issue.
IMO, there should be tests added for the tree grid and hierarchical grid as well, since the current test will pass even if only if (!event.target.closest('igx-grid-cell')) is left.

EDIT: Logged the hGrid selected event issue here.