fix: constrained move mode improvements

[mikeharv]

The basics

• I validated my changes

The details

Resolves

Fixes #10023 #10024 #10025

Proposed Changes

This updates determineConnectionOffset() and updateConnectionPreview() in order to resolve three separate bugs.

1. When determine the connection offset for a drag, use local.getOffsetInBlock() instead of local.x/local.y.
2. Hide connection previews and reset connectionCandidate before calculating block position on workspace.
3. Ignore dragging block when considering bounds of other blocks when calculating the same position.
4. Horizontally align blocks moved to workspace with their most recent connection instead of the left edge of all blocks.

Reason for Changes

1. When blocks are inserted from the toolbox, their RenderedConnection.x and RenderedConenction.y values have not been set and are equal to the coordinates of the block itself. This causes the block to be positioned incorrectly. See Block moved to bad position when inserting from toolbox #10023

2-3. Blocks were being moved onto the workspace further down than was necessary because the size of the content was influenced by the prior block position. By first hiding the preview and filtering out the dragging block from the content, we can get accurate bounds. See #10025

4. By moving the block below the previous connection, we effectively guarantee that moving the block back up will result in moving to the last connection as expected. This solution is consistent screen reader mode enabled and disabled. See Moving blocks to closest connection is confusing when moving from below-blocks workspace position #10024

This also adds a slight indent to the position of statements as the nextConnection of a block is slightly offset: