Replacing reporter hides previous reporter under block

[ErikMejerHansen]

Expected Behavior

All added blocks and reporters should be visible all the time.

Actual Behavior

If you replace a reporter the previous reporter may get hidden under other blocks in stack.

Steps to Reproduce

Add two blocks in a stack.
Add reporter to first block
Replace reporter with a new reporter
See that the previous reporter gets paced behind block

[paulkaplan]

When reporters get replaced, they are offset by a fixed amount (see https://github.com/LLK/scratch-blocks/blob/develop/core/rendered_connection.js#L97-L106, the constant controlling it is Blockly.SNAP_RADIUS). One possible solution would be to make the bumpAwayFrom_ function smarter, taking into account the bounds of the block/stack of the staticConnection.

Another issue here is that while bumpAwayFrom_ tries to raise the block to the top z-index-wise (see the comment on line 94 of that file), it is being thwarted by the InsertionMarkerManager#applyConnections which, after applying the connection and calling bumpAway, promotes the newly edited block to the top (see https://github.com/LLK/scratch-blocks/blob/develop/core/insertion_marker_manager.js#L210). I'm not sure we would want to change that behavior, just wanted to call it out as another aspect to the problem in the GIF. I think the first thing I mentioned about being smarter about bumping the disconnected block would be better.

[thisandagain]

/cc @picklesrus