feat(GridBase): Apply spec for server-side rendering for relative gri…

[MayaKirova]

…d sizes.

Closes #15202

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

[MayaKirova]

@dkamburov @ChronosSF

FYI, the grid will now retain 100% size (width/height) from the SSR render, however note that things inside the grid may still flicker during hydration on the client.

For example:

• Scrollbars may show, since we're going from an empty grid to a grid with data.

• Columns that have relative size (in %), may change their size after hydration (and as a result of that also spawn a scrollbar). This makes sense because they were originally measured to the size the sever has used for pre-render.

  So it looks similar to this, when hydration occurs:
  

[mddragnev]

@MayaKirova If you have a grid width a fixed sizes ( let say 600px width and height) then the data should be rendered on the server but it doesnt. It renders on the client

[ChronosSF]

This PR needs to update the changelog. It's actually one of the features we want to promote for 19.2.