[igxPivot] Add empty dimension and values template.

[MayaKirova]

Closes #10977

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

[mddragnev]

@MayaKirova
When initially starting the dev sample an error is thrown with ExpressionChangedAfterItHasBeenCheckedError exception.

Also, when you open the grid and remove one by one every column and row dimension it makes them disabled but not entirely removing them from the configuration. In this case the message "Pivot grid has no dimensions and values defined" should not show.
Steps to reproduce:

1. Open pivot dev sample
2. Remove all dimensions from the chips

[MayaKirova]

The empty message has been updated to also be applicable when dimensions/values are disabled.

@mddragnev The error seems to originate from master, it does not seem related to templates.