Fix grid migration item copy bug

When migrating from a grid with 2+ copies of the same item to a grid that has less copies of that item, but more than 0, the extra copies don't migrate to the new grid.

Bug: 354946925
Test: ValidGridMigrationUnitTest
Flag: EXEMPT bugfix
Change-Id: I76ad0cb0f5abe9b5bf895c07467fc05986e9fea4
2 files changed