fix(editor): note-edgeless-block loses edit state during shift-click range selection (#14675)

### Problem
●In edgeless mode, when using Shift + click to perform range selection
inside an editing `note-edgeless-block` (click at the starting point,
then hold Shift and click at the end point), the block will unexpectedly
lose its editing and selection state. As a result, subsequent operations
on the selection - such as deleting and moving - no longer work.

●The following video demonstrates this issue:


https://github.com/user-attachments/assets/82c68683-e002-4a58-b011-fe59f7fc9f02

### Solution
●The reason is that this "Shift + click" behavior is being handled by
the default multi-selection logic, which toggles selection mode and
exits the editing state. So I added an `else-if` branch to match this
case.

### After
●The video below shows the behavior after this fix.


https://github.com/user-attachments/assets/18d61108-2089-4def-b2dc-ae13fc5ac333

<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

* **Bug Fixes**
* Improved selection behavior during note editing in multi-select mode
to provide more intuitive interaction when using range selection during
active editing.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->