Duplicate a sprite , the blocks in new sprite remain the same id to previous

[TheWindX]

Expected Behavior

a block should have its own unique ID

Actual Behavior

when duplicate a sprite , the blocks in new sprite remain the same ID to previous

Steps to Reproduce

0. create a block in current workspace
1. get its ID
   ID_1 = Blockly.getMainWorkspace().getTopBlocks()[0].id
2. right click sprite then duplicate
3. in new sprite, get new block's ID depulicated
   ID_2 = Blockly.getMainWorkspace().getTopBlocks()[0].id
4. test, you see
   ID_2 == ID_1

Operating System and Browser

window 10

[thisandagain]

/cc @kchadha @picklesrus @paulkaplan

[kchadha]

@picklesrus, I can take this one since it's actually a VM issue and it's also a bug that causes more project changed state issues. Let me know if you want to keep it or pair on it though.