DV: Update tile selection to defer replace refinement until global selection

[Kaapp]

• There was a bug where we were assigning the same _replacedTileId to all tiles in a tileset with a REFINE replacement type.
• This meant that in our platform when we would try to select the highest priority tile or group from each tileset as a minimum, we would get the root tile for ADD replacements and the whole traversal for REFINE replacements.
• Instead, this PR ensures that we return the entire hierarchy for both types, and updates the GroupedTilesArray to allow merging of two GroupedTilesArray objects by performing the replacement at that level.
• This means that our platform can query for the root tile or group for each tileset and correctly get just that data as a minimum to render. Leaving the remaining data in a second GroupedTilesArray, we can then use the updated API to merge in the remaining tiles up to our rendering budget.

N.B. There are some lerna changes that seemed required now that we are running on yarn 4 w/ corepack internally.

[Kaapp]

I won't merge this, or the corresponding platform PR, until we've gone through guinea pigs testing, but not expecting anything major so prepping these PRs ahead of time.